Label.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / Label.cs / 2 / Label.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Windows.Forms { 
 
    using System;
    using System.Security.Permissions; 
    using System.Collections.Specialized;
    using System.ComponentModel;
    using System.ComponentModel.Design;
    using System.Diagnostics; 
    using System.Drawing;
    using System.Windows.Forms.Internal; 
    using System.Drawing.Design; 
    using System.Drawing.Imaging;
    using System.Runtime.InteropServices; 
    using System.Runtime.Remoting;
    using System.Runtime.Serialization.Formatters;
    using System.Windows.Forms.Layout;
    using Microsoft.Win32; 
    using System.Collections;
    using System.Globalization; 
    using System.Diagnostics.CodeAnalysis; 

 
    /// 
    /// 
    ///    
    ///       Represents a standard Windows label.  
    /// 
    [ 
    ComVisible(true), 
    ClassInterface(ClassInterfaceType.AutoDispatch),
    DefaultProperty("Text"), 
    DefaultBindingProperty("Text"),
    Designer("System.Windows.Forms.Design.LabelDesigner, " + AssemblyRef.SystemDesign),
    ToolboxItem("System.Windows.Forms.Design.AutoSizeToolboxItem," + AssemblyRef.SystemDesign),
    SRDescription(SR.DescriptionLabel) 
    ]
    // If not for FormatControl, we could inherit from ButtonBase and get foreground images for free. 
    public class Label : Control { 

        private static readonly object EVENT_TEXTALIGNCHANGED = new object(); 

        private static readonly BitVector32.Section StateUseMnemonic = BitVector32.CreateSection(1);
        private static readonly BitVector32.Section StateAutoSize    = BitVector32.CreateSection(1, StateUseMnemonic);
        private static readonly BitVector32.Section StateAnimating   = BitVector32.CreateSection(1, StateAutoSize); 
        private static readonly BitVector32.Section StateFlatStyle   = BitVector32.CreateSection((int)FlatStyle.System, StateAnimating);
        private static readonly BitVector32.Section StateBorderStyle = BitVector32.CreateSection((int)BorderStyle.Fixed3D, StateFlatStyle); 
        private static readonly BitVector32.Section StateAutoEllipsis = BitVector32.CreateSection(1, StateBorderStyle); 

        private static readonly int PropImageList  = PropertyStore.CreateKey(); 
        private static readonly int PropImage      = PropertyStore.CreateKey();

        private static readonly int PropTextAlign  = PropertyStore.CreateKey();
        private static readonly int PropImageAlign = PropertyStore.CreateKey(); 
        private static readonly int PropImageIndex = PropertyStore.CreateKey();
 
        /////////////////////////////////////////////////////////////////////// 
        // Label per instance members
        // 
        // Note: Do not add anything to this list unless absolutely neccessary.
        //
        // Begin Members {
 
        // List of properties that are generally set, so we keep them directly on
        // Label. 
        // 

        BitVector32 labelState = new BitVector32(); 
        int         requestedHeight;
        int         requestedWidth;
        LayoutUtils.MeasureTextCache textMeasurementCache;
 
        //Tooltip is shown only if the Text in the Label is cut.
        internal bool showToolTip = false; 
        ToolTip     textToolTip; 
        // This bool suggests that the User has added a toolTip to this label
        // In such a case we should not show the AutoEllipsis tooltip. 
        bool        controlToolTip = false;

        // } End Members
        /////////////////////////////////////////////////////////////////////// 

        ///  
        ///  
        ///    
        ///       Initializes a new instance of the  class. 
        ///    
        /// 
        public Label()
        : base() { 
            // this class overrides GetPreferredSizeCore, let Control automatically cache the result
            SetState2(STATE2_USEPREFERREDSIZECACHE, true); 
 
            SetStyle(ControlStyles.UserPaint |
                     ControlStyles.SupportsTransparentBackColor | 
                     ControlStyles.OptimizedDoubleBuffer, IsOwnerDraw());

            SetStyle(ControlStyles.FixedHeight |
                     ControlStyles.Selectable, false); 

            SetStyle(ControlStyles.ResizeRedraw, true); 
 
            CommonProperties.SetSelfAutoSizeInDefaultLayout(this,true);
 
            labelState[StateFlatStyle]   = (int)FlatStyle.Standard;
            labelState[StateUseMnemonic] = 1;
            labelState[StateBorderStyle] = (int)BorderStyle.None;
 
            TabStop = false;
            requestedHeight = Height; 
            requestedWidth = Width; 
        }
 

        /// 
        /// 
        ///     Indicates whether the control is automatically resized 
        ///       to fit its contents. 
        ///  
        [ 
        SRCategory(SR.CatLayout),
        DefaultValue(false), 
        RefreshProperties(RefreshProperties.All),
        Localizable(true),
        SRDescription(SR.LabelAutoSizeDescr),
        Browsable(true), 
        EditorBrowsable(EditorBrowsableState.Always),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Visible) 
        ] 
        public override bool AutoSize {
            get { 
                return base.AutoSize;
            }
            set {
                if (AutoSize != value) { 
                    base.AutoSize = value;
                    AdjustSize(); 
                } 
            }
        } 

        /// 
        [SRCategory(SR.CatPropertyChanged), SRDescription(SR.ControlOnAutoSizeChangedDescr)]
        [Browsable(true), EditorBrowsable(EditorBrowsableState.Always)] 
        new public event EventHandler AutoSizeChanged
        { 
            add 
            {
                base.AutoSizeChanged += value; 
            }
            remove
            {
                base.AutoSizeChanged -= value; 
            }
        } 
 
        /// 
        ///  
        ///     This property controls the activation handling of bleedover for the text that
        ///    extends beyond the width of the label. 
        /// 
        [ 
        SRCategory(SR.CatBehavior),
        DefaultValue(false), 
        Browsable(true), 
        EditorBrowsable(EditorBrowsableState.Always),
        SRDescription(SR.LabelAutoEllipsisDescr) 
        ]
        public bool AutoEllipsis {
            get {
                return labelState[StateAutoEllipsis] != 0; 
            }
 
            set { 
                if (AutoEllipsis != value) {
                    labelState[StateAutoEllipsis] = value ? 1 : 0; 
                    MeasureTextCache.InvalidateCache();

                    OnAutoEllipsisChanged(/*EventArgs.Empty*/);
 
                    if (value) {
                        if (textToolTip == null) { 
                            textToolTip  = new ToolTip(); 
                        }
                    } 


                    if (ParentInternal != null) {
                        LayoutTransaction.DoLayoutIf(AutoSize,ParentInternal, this, PropertyNames.AutoEllipsis); 
                    }
                    Invalidate(); 
                } 
            }
        } 

        /// 
        /// 
        ///  
        ///    
        ///       Gets or sets the image rendered on the background of the control. 
        ///     
        /// 
        [ 
        SRCategory(SR.CatAppearance),
        Browsable(false), EditorBrowsable(EditorBrowsableState.Never),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden),
        SRDescription(SR.LabelBackgroundImageDescr) 
        ]
        public override Image BackgroundImage { 
            get { 
                return base.BackgroundImage;
            } 
            set {
                base.BackgroundImage = value;
            }
        } 

        ///  
        ///  
        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
        new public event EventHandler BackgroundImageChanged { 
            add {
                base.BackgroundImageChanged += value;
            }
            remove { 
                base.BackgroundImageChanged -= value;
            } 
        } 

        ///  
        /// 
        /// 
        ///    
        ///       Gets or sets the image layout for the background of the control. 
        ///    
        ///  
        [ 
        Browsable(false), EditorBrowsable(EditorBrowsableState.Never)
        ] 
        public override ImageLayout BackgroundImageLayout {
            get {
                return base.BackgroundImageLayout;
            } 
            set {
                base.BackgroundImageLayout = value; 
            } 
        }
 
        /// 
        /// 
        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
        new public event EventHandler BackgroundImageLayoutChanged { 
            add {
                base.BackgroundImageLayoutChanged += value; 
            } 
            remove {
                base.BackgroundImageLayoutChanged -= value; 
            }
        }

        ///  
        /// 
        ///     
        ///       Gets or sets the border style for the control. 
        ///    
        ///  
        [
        SRCategory(SR.CatAppearance),
        DefaultValue(BorderStyle.None),
        DispId(NativeMethods.ActiveX.DISPID_BORDERSTYLE), 
        SRDescription(SR.LabelBorderDescr)
        ] 
        public virtual BorderStyle BorderStyle { 
            get {
                return (BorderStyle)labelState[StateBorderStyle]; 
            }
            set {
                //valid values are 0x0 to 0x2
                if (!ClientUtils.IsEnumValid(value, (int)value, (int)BorderStyle.None, (int)BorderStyle.Fixed3D)){ 
                    throw new InvalidEnumArgumentException("value", (int)value, typeof(BorderStyle));
                } 
 
                if (BorderStyle != value) {
                    labelState[StateBorderStyle] = (int)value; 
                    if (ParentInternal != null) {
                        LayoutTransaction.DoLayoutIf(AutoSize, ParentInternal, this, PropertyNames.BorderStyle);
                    }
                    if (AutoSize) { 
                        AdjustSize();
                    } 
                    RecreateHandle(); 
                }
            } 
        }

        /// 
        ///     Determines whether the current state of the control allows for rendering text using TextRenderer (GDI). 
        ///     See LinkLabel implementation for details.
        ///  
        internal virtual bool CanUseTextRenderer { 
            get{
                return true; 
            }
        }

        ///  
        /// 
        ///  
        ///    Overrides Control.  A Label is a Win32 STATIC control, which we setup here. 
        /// 
        protected override CreateParams CreateParams { 
            [SecurityPermission(SecurityAction.LinkDemand, Flags=SecurityPermissionFlag.UnmanagedCode)]
            get {
                CreateParams cp = base.CreateParams;
                cp.ClassName = "STATIC"; 

                if (OwnerDraw) { 
                    // An unfortunate side effect of this style is Windows sends us WM_DRAWITEM 
                    // messages instead of WM_PAINT, but since Windows insists on repainting
                    // *without* a WM_PAINT after SetWindowText, I don't see much choice. 
                    cp.Style |= NativeMethods.SS_OWNERDRAW;

                    // Since we're owner draw, I don't see any point in setting the
                    // SS_CENTER/SS_RIGHT styles. 
                    //
                    cp.ExStyle &= ~NativeMethods.WS_EX_RIGHT;   // WS_EX_RIGHT overrides the SS_XXXX alignment styles 
                } 

 
                if (!OwnerDraw) {
                    switch(TextAlign) {
                        case ContentAlignment.TopLeft:
                        case ContentAlignment.MiddleLeft: 
                        case ContentAlignment.BottomLeft:
                            cp.Style |= NativeMethods.SS_LEFT; 
                            break; 

                        case ContentAlignment.TopRight: 
                        case ContentAlignment.MiddleRight:
                        case ContentAlignment.BottomRight:
                            cp.Style |= NativeMethods.SS_RIGHT;
                            break; 

                        case ContentAlignment.TopCenter: 
                        case ContentAlignment.MiddleCenter: 
                        case ContentAlignment.BottomCenter:
                            cp.Style |= NativeMethods.SS_CENTER; 
                            break;
                    }
                }
                else 
                    cp.Style |= NativeMethods.SS_LEFT;
 
                switch (BorderStyle) { 
                    case BorderStyle.FixedSingle:
                        cp.Style |= NativeMethods.WS_BORDER; 
                        break;
                    case BorderStyle.Fixed3D:
                        cp.Style |= NativeMethods.SS_SUNKEN;
                        break; 
                }
 
                if (!UseMnemonic) 
                    cp.Style |= NativeMethods.SS_NOPREFIX;
 
                return cp;
            }
        }
 
        /// 
        protected override ImeMode DefaultImeMode { 
            get { 
                return ImeMode.Disable;
            } 
        }

        /// 
        protected override Padding DefaultMargin { 
            get {
                return new Padding(3, 0, 3, 0); 
            } 
        }
 
        /// 
        /// 
        ///     Deriving classes can override this to configure a default size for their control.
        ///     This is more efficient than setting the size in the control's constructor. 
        /// 
        protected override Size DefaultSize { 
            get { 
                return new Size(100, AutoSize ? PreferredHeight : 23);
            } 
        }

        /// 
        [ 
            SRCategory(SR.CatAppearance),
            DefaultValue(FlatStyle.Standard), 
            SRDescription(SR.ButtonFlatStyleDescr) 
        ]
        public FlatStyle FlatStyle { 
            get {
                return (FlatStyle)labelState[StateFlatStyle];
            }
            set { 
                //valid values are 0x0 to 0x3
                if (!ClientUtils.IsEnumValid(value, (int)value, (int)FlatStyle.Flat, (int)FlatStyle.System)) 
                { 
                    throw new InvalidEnumArgumentException("value", (int)value, typeof(FlatStyle));
                } 

                if (labelState[StateFlatStyle] != (int)value) {
                    bool needRecreate = (labelState[StateFlatStyle] == (int)FlatStyle.System) || (value == FlatStyle.System);
 
                    labelState[StateFlatStyle] = (int)value;
 
                    SetStyle(ControlStyles.UserPaint 
                             | ControlStyles.SupportsTransparentBackColor
                             | ControlStyles.OptimizedDoubleBuffer, OwnerDraw); 

                    if (needRecreate) {
                        // this will clear the preferred size cache - it's OK if the parent is null - it would be a NOP.
                        LayoutTransaction.DoLayoutIf(AutoSize, ParentInternal, this, PropertyNames.BorderStyle); 
                        if (AutoSize) {
                            AdjustSize(); 
                        } 
                        RecreateHandle();
                    } 
                    else {
                        Refresh();
                    }
                } 
            }
        } 
 
        /// 
        ///  
        ///    
        ///       Gets or sets the image that is displayed on a .
        ///    
        ///  
        [
        Localizable(true), 
        SRDescription(SR.ButtonImageDescr), 
        SRCategory(SR.CatAppearance)
        ] 
        public Image Image {
            get {
                Image image = (Image)Properties.GetObject(PropImage);
 
                if (image == null && ImageList != null && ImageIndexer.ActualIndex >= 0) {
                    return ImageList.Images[ImageIndexer.ActualIndex]; 
                } 
                else {
                    return image; 
                }
            }
            set {
                if (Image != value) { 
                    StopAnimate();
 
                    Properties.SetObject(PropImage, value); 
                    if (value != null) {
                        ImageIndex = -1; 
                        ImageList = null;
                    }

                    // Hook up the frame changed event 
                    //
                    Animate(); 
                    Invalidate(); 
                }
            } 
        }

        /// 
        ///  
        ///    
        ///       Gets or sets the index value of the images displayed on the 
        ///    . 
        ///    
        ///  
        [
        TypeConverterAttribute(typeof(ImageIndexConverter)),
        Editor("System.Windows.Forms.Design.ImageIndexEditor, " + AssemblyRef.SystemDesign, typeof(UITypeEditor)),
        DefaultValue(-1), 
        Localizable(true),
        RefreshProperties(RefreshProperties.Repaint), 
        SRDescription(SR.ButtonImageIndexDescr), 
        SRCategory(SR.CatAppearance)
        ] 
        public int ImageIndex {
            get {

               if (ImageIndexer != null) { 
                    int index = ImageIndexer.Index;
 
                    if (ImageList != null && (index >= ImageList.Images.Count)) { 
                        return ImageList.Images.Count - 1;
                    } 
                    return index;

                }
                return -1; 
            }
            set { 
                if (value < -1) { 
                    throw new ArgumentOutOfRangeException("ImageIndex", SR.GetString(SR.InvalidLowBoundArgumentEx, "ImageIndex", (value).ToString(CultureInfo.CurrentCulture), (-1).ToString(CultureInfo.CurrentCulture)));
                } 
                if (ImageIndex != value) {
                    if (value != -1) {
                        // Image.set calls ImageIndex = -1
                        Properties.SetObject(PropImage, null); 
                    }
 
                    ImageIndexer.Index = value; 
                    Invalidate();
                } 
            }
        }

        ///  
        /// 
        ///     
        ///       Gets or sets the key accessor for the image list.  This specifies the image 
 	    ///	  from the image list to display on
        ///    . 
        ///    
        /// 
        [
        TypeConverterAttribute(typeof(ImageKeyConverter)), 
        Editor("System.Windows.Forms.Design.ImageIndexEditor, " + AssemblyRef.SystemDesign, typeof(UITypeEditor)),
        DefaultValue(""), 
        Localizable(true), 
        RefreshProperties(RefreshProperties.Repaint),
        SRDescription(SR.ButtonImageIndexDescr), 
        SRCategory(SR.CatAppearance)
        ]
        public string ImageKey {
            get { 

               if (ImageIndexer != null) { 
                   return ImageIndexer.Key; 
               }
               return null; 
            }
            set {
                if (ImageKey != value) {
 
                    // Image.set calls ImageIndex = -1
                    Properties.SetObject(PropImage, null); 
 
                    ImageIndexer.Key = value;
                    Invalidate(); 
                }
            }
        }
 
        internal LabelImageIndexer ImageIndexer{
            get { 
                 bool found; 
                 LabelImageIndexer imageIndexer = Properties.GetObject(PropImageIndex, out found) as LabelImageIndexer;
 
                 // Demand create the ImageIndexer property
                 if ((imageIndexer == null) || (!found)) {
                    imageIndexer = new LabelImageIndexer(this);
                    ImageIndexer = imageIndexer; 
                 }
 
                 return imageIndexer; 
            }
            set { 
                Properties.SetObject(PropImageIndex, value);
            }

        } 

        ///  
        ///  
        ///    
        ///       Gets or sets the images displayed in a . 
        ///    
        /// 
        [
        DefaultValue(null), 
        SRDescription(SR.ButtonImageListDescr),
        RefreshProperties(RefreshProperties.Repaint), 
        SRCategory(SR.CatAppearance) 
        ]
        public ImageList ImageList { 
            get {
                return (ImageList)Properties.GetObject(PropImageList);
            }
            set { 
                if (ImageList != value) {
 
                    EventHandler recreateHandler = new EventHandler(ImageListRecreateHandle); 
                    EventHandler disposedHandler = new EventHandler(DetachImageList);
 
                    // Remove the previous imagelist handle recreate handler
                    //
                    ImageList imageList = ImageList;
                    if (imageList != null) { 
                        imageList.RecreateHandle -= recreateHandler;
                        imageList.Disposed -= disposedHandler; 
                    } 

                    // Make sure we don't have an Image as well as an ImageList 
                    //
                    if (value != null) {
                        Properties.SetObject(PropImage, null); // Image.set calls ImageList = null
                    } 

                    Properties.SetObject(PropImageList, value); 
 
                    // Add the new imagelist handle recreate handler
                    // 
                    if (value != null) {
                        value.RecreateHandle += recreateHandler;
                        value.Disposed += disposedHandler;
                    } 

                    Invalidate(); 
                } 
            }
        } 

        /// 
        /// 
        ///     
        ///       Gets or sets the alignment of the image on the .
        ///     
        ///  
        [
        DefaultValue(ContentAlignment.MiddleCenter), 
        Localizable(true),
        SRDescription(SR.ButtonImageAlignDescr),
        SRCategory(SR.CatAppearance)
        ] 
        public ContentAlignment ImageAlign {
            get { 
                bool found; 
                int imageAlign = Properties.GetInteger(PropImageAlign, out found);
                if (found) { 
                    return (ContentAlignment)imageAlign;
                }
                return ContentAlignment.MiddleCenter;
            } 
            set {
                if (!WindowsFormsUtils.EnumValidator.IsValidContentAlignment(value)) { 
                  throw new InvalidEnumArgumentException("value", (int)value, typeof(ContentAlignment)); 
                }
                if(value != ImageAlign) { 
                    Properties.SetInteger(PropImageAlign, (int)value);
                    LayoutTransaction.DoLayoutIf(AutoSize, ParentInternal, this, PropertyNames.ImageAlign);
                    Invalidate();
                } 
            }
        } 
        /* FxCop rule 'AvoidBuildingNonCallableCode' - Left here in case it is needed in the future. 
        private Rectangle ImageBounds {
            get { 
                Image image = (Image)Properties.GetObject(PropImage);
                return CalcImageRenderBounds(image, ClientRectangle, RtlTranslateAlignment(ImageAlign));
            }
        } 
        */
 
        ///  
        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
        new public ImeMode ImeMode { 
            get {
                return base.ImeMode;
            }
            set { 
                base.ImeMode = value;
            } 
        } 

        ///  
        /// 
        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
        public new event EventHandler ImeModeChanged {
            add { 
                base.ImeModeChanged += value;
            } 
            remove { 
                base.ImeModeChanged -= value;
            } 
        }

        /// 
        ///  
        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
        public new event KeyEventHandler KeyUp { 
            add { 
             base.KeyUp += value;
            } 
            remove {
             base.KeyUp -= value;
            }
        } 

        ///  
        ///  
        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
        public new event KeyEventHandler KeyDown { 
            add {
                 base.KeyDown += value;
            }
            remove { 
                base.KeyDown -= value;
            } 
        } 

        ///  
        /// 
        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
        public new event KeyPressEventHandler KeyPress {
            add { 
             base.KeyPress += value;
            } 
            remove { 
             base.KeyPress -= value;
            } 
        }

        internal LayoutUtils.MeasureTextCache MeasureTextCache {
            get { 
                if (textMeasurementCache == null) {
                    textMeasurementCache = new LayoutUtils.MeasureTextCache(); 
                } 
                return textMeasurementCache;
            } 
        }

        internal virtual bool OwnerDraw {
            get { 
                return IsOwnerDraw();
            } 
        } 

        ///  
        /// 
        ///    
        ///       Gets the height of the control (in pixels), assuming a
        ///       single line of text is displayed. 
        ///    
        ///  
        [ 
        SRCategory(SR.CatLayout),
        Browsable(false), EditorBrowsable(EditorBrowsableState.Advanced), 
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden),
        SRDescription(SR.LabelPreferredHeightDescr)
        ]
        public virtual int PreferredHeight { 
            get { return PreferredSize.Height; }
        } 
 
        /// 
        ///  
        ///    
        ///       Gets the width of the control (in pixels), assuming a single line
        ///       of text is displayed.
        ///     
        /// 
        [ 
        SRCategory(SR.CatLayout), 
        Browsable(false), EditorBrowsable(EditorBrowsableState.Advanced),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden), 
        SRDescription(SR.LabelPreferredWidthDescr)
        ]
        public virtual int PreferredWidth {
            get { return PreferredSize.Width; } 
        }
 
        ///  
        /// 
        ///     Indicates whether 
        ///       the container control background is rendered on the .
        /// 
        [Obsolete("This property has been deprecated. Use BackColor instead.  http://go.microsoft.com/fwlink/?linkid=14202")]
        virtual new protected bool RenderTransparent 
        {
            get { 
                return((Control) this).RenderTransparent; 
            }
            set { 
            }
        }

 
        private bool SelfSizing {
            get { 
                return CommonProperties.ShouldSelfSize(this); 
            }
        } 

        /// 
        /// 
        ///     
        ///       Gets or sets a value indicating whether the user can tab to the
        ///    . 
        ///     
        /// 
        [DefaultValue(false), Browsable(false), EditorBrowsable(EditorBrowsableState.Never)] 
        new public bool TabStop {
            get {
                return base.TabStop;
            } 
            set {
                base.TabStop = value; 
            } 
        }
 
        /// 
        /// 
        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
        new public event EventHandler TabStopChanged { 
            add {
                base.TabStopChanged += value; 
            } 
            remove {
                base.TabStopChanged -= value; 
            }
        }

        ///  
        /// 
        ///     
        ///       Gets or sets the 
        ///       horizontal alignment of the text in the control.
        ///     
        /// 
        [
        SRDescription(SR.LabelTextAlignDescr),
        Localizable(true), 
        DefaultValue(ContentAlignment.TopLeft),
        SRCategory(SR.CatAppearance) 
        ] 
        public virtual ContentAlignment TextAlign {
            get { 
                bool found;
                int textAlign = Properties.GetInteger(PropTextAlign, out found);
                if (found) {
                    return (ContentAlignment)textAlign; 
                }
 
                return ContentAlignment.TopLeft; 
            }
            set { 

                if (!WindowsFormsUtils.EnumValidator.IsValidContentAlignment(value)) {
                    throw new InvalidEnumArgumentException("value", (int)value, typeof(ContentAlignment));
                } 

                if (TextAlign != value) { 
                    Properties.SetInteger(PropTextAlign, (int)value); 
                    Invalidate();
                    //Change the TextAlignment for SystemDrawn Labels .... 
                    if (!OwnerDraw) {
                        RecreateHandle();
                    }
                    OnTextAlignChanged(EventArgs.Empty); 

                } 
            } 
        }
 
        /// 
        /// 
        ///    
        ///       Gets or sets the text in the Label. Since we can have multiline support 
        ///       this property just overides the base to pluck in the Multiline editor.
        ///     
        ///  
        [
        Editor("System.ComponentModel.Design.MultilineStringEditor, " + AssemblyRef.SystemDesign, typeof(UITypeEditor)), 
        SettingsBindable(true)
        ]
        public override string Text {
            get { 
                return base.Text;
            } 
            set { 
                base.Text = value;
            } 
        }


        ///  
        /// 
        ///    [To be supplied.] 
        ///  
        [SRCategory(SR.CatPropertyChanged), SRDescription(SR.LabelOnTextAlignChangedDescr)]
        public event EventHandler TextAlignChanged { 
            add {
                Events.AddHandler(EVENT_TEXTALIGNCHANGED, value);
            }
 
            remove {
                Events.RemoveHandler(EVENT_TEXTALIGNCHANGED, value); 
            } 
        }
 
        /// 
        ///     Determines whether to use compatible text rendering engine (GDI+) or not (GDI).
        /// 
        [ 
        DefaultValue(false),
        SRCategory(SR.CatBehavior), 
        SRDescription(SR.UseCompatibleTextRenderingDescr) 
        ]
        public bool UseCompatibleTextRendering { 
            get{
                if( CanUseTextRenderer ){
                    return base.UseCompatibleTextRenderingInt;
                } 

                // Use compat text rendering (GDI+). 
                return true; 
            }
            set{ 
                if( base.UseCompatibleTextRenderingInt != value ) {
                    base.UseCompatibleTextRenderingInt = value;
                    AdjustSize();
                } 
            }
        } 
 
        /// 
        ///     Determines whether the control supports rendering text using GDI+ and GDI. 
        ///     This is provided for container controls to iterate through its children to set UseCompatibleTextRendering to the same
        ///     value if the child control supports it.
        /// 
        internal override bool SupportsUseCompatibleTextRendering { 
            get {
                return true; 
            } 
        }
 
        /// 
        /// 
        ///    Gets or sets a value indicating whether an ampersand (&) included in the text of
        ///       the control. 
        /// 
        [ 
        SRDescription(SR.LabelUseMnemonicDescr), 
        DefaultValue(true),
        SRCategory(SR.CatAppearance) 
        ]
        public bool UseMnemonic {
            get {
                return labelState[StateUseMnemonic] != 0; 
            }
 
            set { 

                if (UseMnemonic != value) { 
                   labelState[StateUseMnemonic] = value ? 1 : 0;
                   MeasureTextCache.InvalidateCache();

 
                   // The size of the label need to be adjusted when the Mnemonic
                   // is set irrespective of auto-sizing 
                   using (LayoutTransaction.CreateTransactionIf(AutoSize, ParentInternal, this, PropertyNames.Text)) { 
                      AdjustSize();
                      Invalidate(); 
                   }

                   //set windowStyle directly instead of recreating handle to increase efficiency
                   if (IsHandleCreated) { 
                      int style = this.WindowStyle;
                      if (!UseMnemonic) { 
 
                         style |= NativeMethods.SS_NOPREFIX;
                      } 
                      else {
                         style &= ~NativeMethods.SS_NOPREFIX;
                      }
                      this.WindowStyle = style; 
                   }
                } 
            } 
        }
 

        /// 
        ///     Updates the control in response to events that could affect either
        ///     the size of the control, or the size of the text within it. 
        /// 
        ///  
        internal void AdjustSize() { 
            if (!SelfSizing) {
                return; 
            }

            // the rest is here for RTM compat.
 
            // If width and/or height are constrained by anchoring, don't adjust control size
            // to fit around text, since this will cause us to lose the original anchored size. 
            if (!AutoSize && 
                ((this.Anchor & (AnchorStyles.Left | AnchorStyles.Right)) == (AnchorStyles.Left | AnchorStyles.Right) ||
                 (this.Anchor & (AnchorStyles.Top | AnchorStyles.Bottom)) == (AnchorStyles.Top | AnchorStyles.Bottom))) { 
                return;
            }

            // Resize control to fit around current text 
            //
            int saveHeight = requestedHeight; 
            int saveWidth = requestedWidth; 
            try {
                Size preferredSize = (AutoSize) ? PreferredSize : new Size(saveWidth, saveHeight); 
                Size = preferredSize;
            }
            finally {
                requestedHeight = saveHeight; 
                requestedWidth = saveWidth;
            } 
        } 

        internal void Animate() { 
            Animate(!DesignMode && Visible && Enabled && ParentInternal != null);
        }

        internal void StopAnimate() { 
            Animate(false);
        } 
 
        private void Animate(bool animate) {
            bool currentlyAnimating = labelState[StateAnimating] != 0; 
            if (animate != currentlyAnimating) {
                Image image = (Image)Properties.GetObject(PropImage);
                if (animate) {
                    if (image != null) { 
                        ImageAnimator.Animate(image, new EventHandler(this.OnFrameChanged));
                        labelState[StateAnimating] = animate ? 1 : 0; 
                    } 
                }
                else { 
                    if (image != null) {
                        ImageAnimator.StopAnimate(image, new EventHandler(this.OnFrameChanged));
                        labelState[StateAnimating] = animate ? 1 : 0;
                    } 
                }
            } 
        } 

        ///  
        /// 
        ///    [To be supplied.]
        /// 
        protected Rectangle CalcImageRenderBounds(Image image, Rectangle r, ContentAlignment align) { 
            Size pointImageSize = image.Size;
 
            int xLoc = r.X + 2; 
            int yLoc = r.Y + 2;
 
            if ((align & WindowsFormsUtils.AnyRightAlign) !=0) {
                xLoc = (r.X+r.Width - 4)-pointImageSize.Width;
            }
            else if ((align & WindowsFormsUtils.AnyCenterAlign) != 0) { 
                xLoc = r.X + (r.Width - pointImageSize.Width)/2;
            } 
 

            if ((align & WindowsFormsUtils.AnyBottomAlign) != 0) { 
                yLoc = (r.Y+r.Height - 4)-pointImageSize.Height;
            }
            else if ((align & WindowsFormsUtils.AnyTopAlign) != 0) {
                yLoc = r.Y + 2; 
            }
            else { 
                yLoc = r.Y + (r.Height - pointImageSize.Height)/2; 
            }
 
            return new Rectangle(xLoc, yLoc, pointImageSize.Width, pointImageSize.Height);
        }

 
        /// 
        protected override AccessibleObject CreateAccessibilityInstance() { 
            return new LabelAccessibleObject(this); 
        }
 
        /// 
        ///     Get StringFormat object for rendering text using GDI+ (Graphics).
        /// 
        internal virtual StringFormat CreateStringFormat() { 
            return ControlPaint.CreateStringFormat( this, this.TextAlign, this.AutoEllipsis, this.UseMnemonic );
        } 
 
        private TextFormatFlags CreateTextFormatFlags() {
            return CreateTextFormatFlags(this.Size - GetBordersAndPadding()); 
        }
        /// 
        ///     Get TextFormatFlags flags for rendering text using GDI (TextRenderer).
        ///  
        internal virtual TextFormatFlags CreateTextFormatFlags(Size constrainingSize){
 
            // PREFERRED SIZE CACHING: 
            // Please read if you're adding a new TextFormatFlag.
            // whenever something can change the TextFormatFlags used 
            // MeasureTextCache.InvalidateCache() should be called so we can approprately clear.

            TextFormatFlags flags = ControlPaint.CreateTextFormatFlags( this, this.TextAlign, this.AutoEllipsis, this.UseMnemonic );
 
            // Remove WordBreak if the size is large enough to display all the text.
            if (!MeasureTextCache.TextRequiresWordBreak(Text, Font, constrainingSize, flags)) { 
                // The effect of the TextBoxControl flag is that in-word line breaking will occur if needed, this happens when AutoSize 
                // is false and a one-word line still doesn't fit the binding box (width).  The other effect is that partially visible
                // lines are clipped; this is how GDI+ works by default. 
                flags &= ~(TextFormatFlags.WordBreak | TextFormatFlags.TextBoxControl);
            }

            return flags; 
        }
 
        private void DetachImageList(object sender, EventArgs e) { 
            ImageList = null;
        } 


        /// 
        ///  
        ///    [To be supplied.]
        ///  
        protected override void Dispose(bool disposing) { 
            if (disposing) {
                StopAnimate(); 
                // VSWhidbey 318551: holding on to images and image list is a memory leak.
                if (ImageList != null) {
                    ImageList.Disposed       -= new EventHandler(this.DetachImageList);
                    ImageList.RecreateHandle -= new EventHandler(ImageListRecreateHandle); 
                    Properties.SetObject(PropImageList, null);
                } 
                if (Image != null) { 
                    Properties.SetObject(PropImage, null);
                } 

                //Dipose the tooltip if one present..
                if (textToolTip != null) {
                    textToolTip.Dispose(); 
                    textToolTip = null;
                } 
                controlToolTip = false; 
            }
            base.Dispose(disposing); 
        }

        /// 
        ///  
        ///    
        ///       Draws an  within the specified bounds. 
        ///     
        /// 
        protected void DrawImage(System.Drawing.Graphics g, Image image, Rectangle r, ContentAlignment align) { 
            Rectangle loc = CalcImageRenderBounds(image, r, align);

            if (!Enabled) {
                ControlPaint.DrawImageDisabled(g, image, loc.X, loc.Y, BackColor); 
            }
            else { 
                g.DrawImage(image, loc.X, loc.Y, image.Width, image.Height); 
            }
        } 

        /// 
        /// 
        ///  
        ///    
        ///       This Function returns the number of lines in the label Text. 
        ///     
        /// 
        /* FxCop rule 'AvoidBuildingNonCallableCode' - Left here in case it is needed in the future. 
        private ArrayList GetLines() {
            string text = Text;
            ArrayList list = new ArrayList();
 
            int lineStart = 0;
            while (lineStart < text.Length) { 
                int lineEnd = lineStart; 
                for (; lineEnd < text.Length; lineEnd++) {
                    char c = text[lineEnd]; 
                    if (c == '\r' || c == '\n')
                        break;
                }
 
                string line = text.Substring(lineStart, lineEnd - lineStart);
                list.Add(line); 
 
                // Treat "\r", "\r\n", and "\n" as new lines
                if (lineEnd < text.Length && text[lineEnd] == '\r') 
                    lineEnd++;
                if (lineEnd < text.Length && text[lineEnd] == '\n')
                    lineEnd++;
 
                lineStart = lineEnd;
            } 
            return list; 
        }
        */ 
        private Size GetBordersAndPadding() {
           Size bordersAndPadding = Padding.Size;

           // COMPAT VSW 248415: Everett added random numbers to the height of the label 
           if (UseCompatibleTextRendering) {
              //Always return the Fontheight + some buffer else the Text gets clipped for Autosize = true.. 
              //(bug 118909) 
              if (BorderStyle != BorderStyle.None) {
                  bordersAndPadding.Height += 6; // taken from Everett.PreferredHeight 
                  bordersAndPadding.Width += 2; // taken from Everett.PreferredWidth
              }
              else {
                  bordersAndPadding.Height += 3; // taken from Everett.PreferredHeight 
              }
           } 
           else { 
              // in Whidbey we'll actually ask the control the border size.
 
              bordersAndPadding +=  SizeFromClientSize(Size.Empty);
              if (BorderStyle == BorderStyle.Fixed3D) {
                  bordersAndPadding += new Size(2, 2);
              } 
           }
           return bordersAndPadding; 
 
       }
 

        public override Size GetPreferredSize(Size proposedSize) {
            //make sure the behavior is consistent with GetPreferredSizeCore
            if (proposedSize.Width == 1) { 
                proposedSize.Width = 0;
            } 
            if (proposedSize.Height == 1) { 
                proposedSize.Height = 0;
            } 
            return base.GetPreferredSize(proposedSize);
        }

        internal virtual bool UseGDIMeasuring() { 
            return (FlatStyle == FlatStyle.System || !UseCompatibleTextRendering);
        } 
 
        [SuppressMessage("Microsoft.Globalization", "CA1303:DoNotPassLiteralsAsLocalizedParameters")] // See ComboBox.cs GetComboHeight
        internal override Size GetPreferredSizeCore(Size proposedConstraints) { 
            Size bordersAndPadding = GetBordersAndPadding();
            // Subtract border area from constraints
            proposedConstraints -= bordersAndPadding;
 
            // keep positive
            proposedConstraints = LayoutUtils.UnionSizes(proposedConstraints,Size.Empty); 
 
            Size requiredSize;
 
            //
            // TEXT Measurement
            //
 
            if (string.IsNullOrEmpty(Text)) {
                // COMPAT VSW 248415: empty labels return the font height + borders 
                using (WindowsFont font = WindowsFont.FromFont(this.Font)) { 
                    // this is the character that Windows uses to determine the extent
                    requiredSize = WindowsGraphicsCacheManager.MeasurementGraphics.GetTextExtent("0", font); 
                    requiredSize.Width = 0;
                }
            }
            else if (UseGDIMeasuring()) { 
                TextFormatFlags format = FlatStyle == FlatStyle.System ? TextFormatFlags.Default : CreateTextFormatFlags(proposedConstraints);
                requiredSize = MeasureTextCache.GetTextSize(Text, Font, proposedConstraints, format); 
            } 
            else {
                // GDI+ rendering. 
                using (Graphics measurementGraphics = WindowsFormsUtils.CreateMeasurementGraphics()) {
                    using (StringFormat stringFormat = CreateStringFormat()) {
                        SizeF bounds = (proposedConstraints.Width == 1) ?
                            new SizeF(0, proposedConstraints.Height) : 
                            new SizeF(proposedConstraints.Width, proposedConstraints.Height);
 
                        requiredSize = Size.Ceiling(measurementGraphics.MeasureString(Text, Font, bounds, stringFormat)); 
                    }
                } 

            }

            requiredSize += bordersAndPadding; 

            return requiredSize; 
        } 

        ///  
        ///     This method is to be called by LabelDesigner, using private reflection, to get the location of the text snaplines.
        /// 
        [
            // This method is called by LabelDesigner, using private reflection. 
            System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")
        ] 
        private int GetLeadingTextPaddingFromTextFormatFlags(){ 
            if( !IsHandleCreated ){
                return 0; 
            }

            //If we are using GDI+ the code below will not work, except
            //if the style is FlatStyle.System since GDI will be used in that case. 
            if (UseCompatibleTextRendering && FlatStyle != FlatStyle.System) {
                return 0; 
            } 

            using( WindowsGraphics wg = WindowsGraphics.FromHwnd(this.Handle) ){ 
                TextFormatFlags flags = CreateTextFormatFlags();

                if( (flags & TextFormatFlags.NoPadding ) == TextFormatFlags.NoPadding ){
                    wg.TextPadding = TextPaddingOptions.NoPadding; 
                }
                else if( (flags & TextFormatFlags.LeftAndRightPadding ) == TextFormatFlags.LeftAndRightPadding ){ 
                    wg.TextPadding = TextPaddingOptions.LeftAndRightPadding; 
                }
 
                using (WindowsFont wf = WindowsGraphicsCacheManager.GetWindowsFont(this.Font)) {
                    IntNativeMethods.DRAWTEXTPARAMS dtParams = wg.GetTextMargins(wf);

                    // This is actually leading margin. 
                    return dtParams.iLeftMargin;
                } 
            } 
        }
 
        private void ImageListRecreateHandle(object sender, EventArgs e) {
            if (IsHandleCreated) {
                Invalidate();
            } 
        }
 
        ///  
        ///     Specifies whether the control is willing to process mnemonics when hosted in an container ActiveX (Ax Sourcing).
        ///  
        internal override bool IsMnemonicsListenerAxSourced
        {
            get{
                return true; 
            }
        } 
 
        /// 
        ///    This method is required because the Label constructor needs to know if the control is OwnerDraw but it should 
        ///    not call the virtual property for the following reason (from FxCop rule 'ConstructorsShouldNotCallBaseClassVirtualMethods'):
        ///    Virtual methods defined on the class should not be called from constructors. If a derived class has overridden
        ///    the method, the derived class version will be called (before the derived class constructor is called).
        ///  
        internal bool IsOwnerDraw(){
            return FlatStyle != FlatStyle.System; 
        } 

        ///  
        /// 
        /// 
        ///    
        ///       Raises the  event. 
        ///    
        ///  
        protected override void OnMouseEnter(EventArgs e) { 
            if (!controlToolTip && !DesignMode && AutoEllipsis && showToolTip && textToolTip != null) {
 
                // SECREVIEW: VSWhidbey 531915 - ToolTip should show in internet zone
                IntSecurity.AllWindows.Assert();
                try {
                    controlToolTip = true; 
                    textToolTip.Show(WindowsFormsUtils.TextWithoutMnemonics(Text), this);
                } 
                finally { 
                    System.Security.CodeAccessPermission.RevertAssert();
                    controlToolTip = false; 
                }

            }
            base.OnMouseEnter(e); 
        }
 
        ///  
        /// 
        ///  
        ///    
        ///       Raises the  event.
        ///    
        ///  
        [SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
        [SuppressMessage("Microsoft.Security", "CA2118:ReviewSuppressUnmanagedCodeSecurityUsage")] 
        protected override void OnMouseLeave(EventArgs e) { 
            if (!controlToolTip && textToolTip != null && textToolTip.GetHandleCreated()) {
                    textToolTip.RemoveAll(); 
                    // SECREVIEW: VSWhidbey 531915 - ToolTip should show in internet zone
                    IntSecurity.AllWindows.Assert();
                    try {
                        textToolTip.Hide(this); 
                    }
                    finally { 
                        System.Security.CodeAccessPermission.RevertAssert(); 
                    }
            } 

            base.OnMouseLeave(e);
        }
 
        private void OnFrameChanged(object o, EventArgs e) {
            if (Disposing || IsDisposed) { 
                return; 
            }
            if (IsHandleCreated && InvokeRequired) 
            {
                BeginInvoke(new EventHandler(this.OnFrameChanged), o, e);
                return;
            } 
            if (IsWindowObscured) {
                StopAnimate(); 
                return; 
            }
            Invalidate(); 
        }

        /// 
        ///  
        ///    [To be supplied.]
        ///  
        protected override void OnFontChanged(EventArgs e) { 
            MeasureTextCache.InvalidateCache();
            base.OnFontChanged(e); 
            AdjustSize();
            Invalidate();
        }
 

        [SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")] 
        [SuppressMessage("Microsoft.Security", "CA2118:ReviewSuppressUnmanagedCodeSecurityUsage")] 
        protected override void OnHandleDestroyed(EventArgs e) {
            base.OnHandleDestroyed(e); 
            if (textToolTip != null && textToolTip.GetHandleCreated())
            {
                textToolTip.DestroyHandle();
            } 
        }
 
        ///  
        /// 
        ///    [To be supplied.] 
        /// 
        protected override void OnTextChanged(EventArgs e) {

            using(LayoutTransaction.CreateTransactionIf(AutoSize, ParentInternal, this, PropertyNames.Text)) { 
                MeasureTextCache.InvalidateCache();
                base.OnTextChanged(e); 
                AdjustSize(); 
                Invalidate();
            } 
        }

        /// 
        ///  
        ///    [To be supplied.]
        ///  
        protected virtual void OnTextAlignChanged(EventArgs e) { 
            EventHandler eh = Events[EVENT_TEXTALIGNCHANGED] as EventHandler;
            if (eh != null) { 
                 eh(this, e);
            }
        }
 
        protected override void OnPaddingChanged(EventArgs e) {
            base.OnPaddingChanged(e); 
            AdjustSize(); 
        }
 
        /// 
        /// 
        /// 
        ///  
        protected override void OnPaint(PaintEventArgs e) {
            Animate(); 
 
            Rectangle face = LayoutUtils.DeflateRect(ClientRectangle, Padding);
            ImageAnimator.UpdateFrames(); 
            Image i = this.Image;
            if (i != null) {
                DrawImage(e.Graphics, i, face, RtlTranslateAlignment(ImageAlign));
            } 

            Color color; 
            IntPtr hdc = e.Graphics.GetHdc(); 

            try{ 
                using(WindowsGraphics wg = WindowsGraphics.FromHdc( hdc )) {
                    color = wg.GetNearestColor((Enabled) ? ForeColor : DisabledColor);
                }
            } 
            finally{
                e.Graphics.ReleaseHdc(); 
            } 

            // Do actual drawing 

            if (AutoEllipsis) {
                Rectangle clientRect = this.ClientRectangle;
                Size preferredSize = GetPreferredSize(new Size(clientRect.Width, clientRect.Height)); 
                showToolTip = (clientRect.Width < preferredSize.Width || clientRect.Height < preferredSize.Height);
            } 
            else { 
                showToolTip = false;
            } 

            if (UseCompatibleTextRendering) {
                using (StringFormat stringFormat = CreateStringFormat()) {
                    if (Enabled) { 
                        using (Brush brush = new SolidBrush(color)) {
                            e.Graphics.DrawString(Text, Font, brush, face, stringFormat); 
                        } 
                    }
                    else { 
                        ControlPaint.DrawStringDisabled(e.Graphics, Text, Font, color, face, stringFormat);
                    }
                }
            } 
            else{
                TextFormatFlags flags = CreateTextFormatFlags(); 
 
                if (Enabled) {
                    TextRenderer.DrawText(e.Graphics, Text, Font, face, color, flags); 
                }
                else {
                    //Theme specs -- if the backcolor is darker than Control, we use
                    // ControlPaint.Dark(backcolor).  Otherwise we use ControlDark. 
                    // see VS#357226
                    Color disabledTextForeColor = TextRenderer.DisabledTextColor(this.BackColor); 
                    TextRenderer.DrawText(e.Graphics, Text, Font, face, disabledTextForeColor, flags); 
                }
            } 

            base.OnPaint(e); // raise paint event
        }
 
        /// 
        ///     Overriden by LinkLabel. 
        ///  
        internal virtual void OnAutoEllipsisChanged(/*EventArgs e*/) {
        } 

        /// 
        /// 
        ///    [To be supplied.] 
        /// 
        protected override void OnEnabledChanged(EventArgs e) { 
            base.OnEnabledChanged(e); 
            Animate();
        } 


        /// 
        ///  
        ///    [To be supplied.]
        ///  
        protected override void OnParentChanged(EventArgs e) { 
            base.OnParentChanged(e);
            if (SelfSizing) { 
                // VSWhidbey 368232: in the case of SelfSizing
                // we dont know what size to be until we're parented
                AdjustSize();
            } 
            Animate();
        } 
 
        protected override void OnRightToLeftChanged(EventArgs e) {
            MeasureTextCache.InvalidateCache(); 
            base.OnRightToLeftChanged(e);
        }

        ///  
        /// 
        ///    [To be supplied.] 
        ///  
        protected override void OnVisibleChanged(EventArgs e) {
            base.OnVisibleChanged(e); 
            Animate();
        }

        internal override void PrintToMetaFileRecursive(HandleRef hDC, IntPtr lParam, Rectangle bounds) { 
            base.PrintToMetaFileRecursive(hDC, lParam, bounds);
 
            using (WindowsFormsUtils.DCMapping mapping = new WindowsFormsUtils.DCMapping(hDC, bounds)) { 
                using(Graphics g = Graphics.FromHdcInternal(hDC.Handle)) {
                    ControlPaint.PrintBorder(g, new Rectangle(Point.Empty, Size), BorderStyle, Border3DStyle.SunkenOuter); 
                }
            }
        }
 

 
        ///  
        /// 
        ///  
        ///    
        ///       Overrides Control. This is called when the user has pressed an Alt-CHAR
        ///       key combination and determines if that combination is an interesting
        ///       mnemonic for this control. 
        ///    
        ///  
        [UIPermission(SecurityAction.LinkDemand, Window=UIPermissionWindow.AllWindows)] 
        protected internal override bool ProcessMnemonic(char charCode) {
            if (UseMnemonic && IsMnemonic(charCode, Text) && CanProcessMnemonic()) { 
                Control parent = ParentInternal;
                if (parent != null) {
                    // SECREVIEW: This assert is required because the call to SelectNextControl will generate a call to SetActiveControl which have a demand,
                    //            it is safe since no input from user code is processed while setting the active control originated this way. 
                    //
                    IntSecurity.ModifyFocus.Assert(); 
                    try { 
                        if (parent.SelectNextControl(this, true, false, true, false)) {
                            if (!parent.ContainsFocus) { 
                                parent.Focus();
                            }
                        }
                    } 
                    finally {
                        System.Security.CodeAccessPermission.RevertAssert(); 
                    } 
                }
                return true; 
            }
            return false;
        }
 
        /// 
        ///  
        ///    Overrides Control.setBoundsCore to enforce autoSize. 
        /// 
        ///  
        protected override void SetBoundsCore(int x, int y, int width, int height, BoundsSpecified specified) {
            if ((specified & BoundsSpecified.Height) != BoundsSpecified.None)
                requestedHeight = height;
            if ((specified & BoundsSpecified.Width) != BoundsSpecified.None) 
                requestedWidth = width;
 
            if (AutoSize && SelfSizing) { 
                Size preferredSize = PreferredSize;
                width = preferredSize.Width; 
                height = preferredSize.Height;
            }

            base.SetBoundsCore(x, y, width, height, specified); 

            Debug.Assert(!AutoSize || (AutoSize && !SelfSizing) || Size == PreferredSize, 
                "It is SetBoundsCore's responsibility to ensure Size = PreferredSize when AutoSize is true."); 
        }
 
        private void ResetImage() {
            Image = null;
        }
 
        private bool ShouldSerializeImage() {
            return Properties.GetObject(PropImage) != null; 
        } 

 
        /// 
        /// 
        ///     Called by ToolTip to poke in that Tooltip into this ComCtl so that the Native ChildToolTip is not exposed.
        ///  
        /// 
        internal void SetToolTip(ToolTip toolTip) { 
            if (toolTip != null && !controlToolTip) { 
                controlToolTip = true;
            } 
        }

        /// 
        ///  
        ///    Returns a string representation for this control.
        ///  
        ///  
        public override string ToString() {
            string s = base.ToString(); 
            return s + ", Text: " + Text;
        }

        ///  
        /// 
        ///  
        ///     
        ///       Overrides Control. This processes certain messages that the Win32 STATIC
        ///       class would normally override. 
        ///    
        /// 
        [SecurityPermission(SecurityAction.LinkDemand, Flags=SecurityPermissionFlag.UnmanagedCode)]
        protected override void WndProc(ref Message m) { 
            switch (m.Msg) {
                case NativeMethods.WM_NCHITTEST: 
                    // label returns HT_TRANSPARENT for everything, so all messages get 
                    // routed to the parent.  Change this so we can tell what's going on.
                    // 
                    Rectangle rectInScreen = this.RectangleToScreen(new Rectangle(0, 0, Width, Height));
                    Point pt = new Point(unchecked((int)(long)m.LParam));
                    m.Result = (IntPtr)((rectInScreen.Contains(pt) ? NativeMethods.HTCLIENT : NativeMethods.HTNOWHERE));
                    break; 

                default: 
                    base.WndProc(ref m); 
                    break;
            } 
        }

        [System.Runtime.InteropServices.ComVisible(true)]
        internal class LabelAccessibleObject : ControlAccessibleObject { 

            public LabelAccessibleObject(Label owner) : base(owner) { 
            } 

            ///  
            ///    [To be supplied.]
            /// 
            public override AccessibleRole Role {
                get { 
                    AccessibleRole role = Owner.AccessibleRole;
                    if (role != AccessibleRole.Default) { 
                        return role; 
                    }
                    return AccessibleRole.StaticText; 
                }
            }
        }
    } 

 
 
    /// 
    ///  
    /// 
    ///    
    ///            Override ImageList.Indexer to support Label's ImageList semantics.
    ///     
    /// 
    internal class LabelImageIndexer : ImageList.Indexer { 
           private Label owner; 
           private bool useIntegerIndex = true;
 
           public LabelImageIndexer(Label owner) {
              this.owner = owner;
           }
 
           public override ImageList ImageList {
                get { return (owner == null) ? null : owner.ImageList; } 
 
                set { Debug.Assert(false, "Setting the image list in this class is not supported");}
           } 


           public override string Key {
                get { return base.Key; } 
                set {
                      base.Key = value; 
                      useIntegerIndex = false; 
                }
           } 

           public override int Index {
                get { return base.Index; }
                set { 
                      base.Index = value;
                      useIntegerIndex = true; 
                } 

           } 


           public override int ActualIndex  {
                get { 
                    if (useIntegerIndex) {
                        // The behavior of label is to return the last item in the Images collection 
                        // if the index is currently set higher than the count. 
                        return (Index < ImageList.Images.Count) ? Index : ImageList.Images.Count - 1;
                    } 
                    else if (ImageList != null) {
                        return ImageList.Images.IndexOfKey(Key);
                    }
 
                    return -1;
                } 
            } 

 
        }

}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

Link Menu

Network programming in C#, Network Programming in VB.NET, Network Programming in .NET
This book is available now!
Buy at Amazon US or
Buy at Amazon UK