DataGridColumn.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / WinForms / Managed / System / WinForms / DataGridColumn.cs / 1305376 / DataGridColumn.cs

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

namespace System.Windows.Forms{ 
    using System.Security.Permissions; 
    using System.Runtime.Remoting;
    using System.ComponentModel; 
    using System;
    using System.Collections;
    using System.Windows.Forms;
    using System.Drawing; 
    using System.Diagnostics;
    using System.Diagnostics.CodeAnalysis; 
    using Microsoft.Win32; 
    using System.Runtime.InteropServices;
 
    /// 
    /// 
    ///    [To be supplied.]
    ///  
    public interface IDataGridColumnStyleEditingNotificationService {
        ///  
        void ColumnStartedEditing(Control editingControl); 
    }
 
    /// 
    /// 
    ///    Specifies the appearance and text formatting and behavior of
    ///       a  control column. 
    /// 
    [ 
    ToolboxItem(false), 
    DesignTimeVisible(false),
    DefaultProperty("Header"), 
    System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1012:AbstractTypesShouldNotHaveConstructors") // Shipped in Everett
    ]
    public abstract class DataGridColumnStyle : Component, IDataGridColumnStyleEditingNotificationService {
 
        private HorizontalAlignment alignment            = HorizontalAlignment.Left;
        // private SolidBrush         alternatingBackBrush = null; 
        // private SolidBrush     backBrush            = null; 
        // SolidBrush    foreBrush            = null;
        private PropertyDescriptor propertyDescriptor = null; 
        private DataGridTableStyle dataGridTableStyle        = null;
        private Font         font                 = null;
        internal int         fontHeight           = -1;
        private string       mappingName       = ""; 
        private string       headerName       = "";
        private bool         invalid              = false; 
        private string       nullText            = SR.GetString(SR.DataGridNullText); 
        private bool         readOnly             = false;
        private bool         updating             = false; 
        //private bool        visible              = true;
        internal int         width                = -1;
        private bool         isDefault            = false;
        AccessibleObject     headerAccessibleObject = null; 

        private static readonly object EventAlignment                   = new object(); 
        private static readonly object EventPropertyDescriptor          = new object(); 
        private static readonly object EventHeaderText                  = new object();
        private static readonly object EventMappingName                 = new object(); 
        private static readonly object EventNullText                    = new object();
        private static readonly object EventReadOnly                    = new object();
        private static readonly object EventWidth                       = new object();
 
        /// 
        ///  
        ///    In a derived class, 
        ///       initializes a new instance of the  class.
        ///  
        public DataGridColumnStyle() {
        }

        ///  
        /// 
        /// Initializes a new instance of the  class with the specified . 
        ///  
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")] // Shipped like this in Everett.
        public DataGridColumnStyle(PropertyDescriptor prop) : this() { 
            this.PropertyDescriptor = prop;
            if (prop != null)
                this.readOnly = prop.IsReadOnly;
        } 

        internal DataGridColumnStyle(PropertyDescriptor prop, bool isDefault) : this(prop) { 
            this.isDefault = isDefault; 
            if (isDefault) {
                // take the header name from the property name 
                this.headerName = prop.Name;
                this.mappingName = prop.Name;
            }
        } 

#if DEBUG 
        internal bool IsDefault { 
            get {
                return this.isDefault; 
            }
        }
#endif // debug
 
        // =-----------------------------------------------------------------
        // =        Properties 
        // =----------------------------------------------------------------- 
        /// 
        ///  
        ///       Gets or sets the alignment of text in a column.
        /// 
        [SRCategory(SR.CatDisplay),
        Localizable(true), 
        DefaultValue(HorizontalAlignment.Left)]
        public virtual HorizontalAlignment Alignment { 
            get { 
                return alignment;
            } 
            set {
               //valid values are 0x0 to 0x2.
               if (!ClientUtils.IsEnumValid(value, (int)value, (int)HorizontalAlignment.Left, (int)HorizontalAlignment.Center)){
                    throw new InvalidEnumArgumentException("value", (int)value, typeof(DataGridLineStyle)); 
               }
                if (alignment != value) { 
                    alignment = value; 
                    OnAlignmentChanged(EventArgs.Empty);
                    Invalidate(); 
                 }
            }
        }
 
        /// 
        public event EventHandler AlignmentChanged { 
            add { 
                Events.AddHandler(EventAlignment, value);
            } 
            remove {
                Events.RemoveHandler(EventAlignment, value);
            }
        } 

        /* 
        ///  
        ///    Gets or sets the background color of alternating rows for a ledger
        ///       appearance. 
        /// 
        /// 
        /// A  that represents the alternating background
        ///    color. The default is the  of the 
        ///    control.
        ///  
        ///  
        ///    Use this property to set a custom alternating color for each column displayed
        ///       in the  control. 
        /// 
        /// 
        /// The following example sets the  property of a specific 
        /// to yellow. 
        /// Private Sub SetColumnAlternatingBackColor()
        ///    ' Create a color object. 
        ///    Dim c As System.Drawing.Color 
        ///    c = System.Drawing.Color.Yellow
        ///    ' Declare an object variable for the DataGridColumnStyle. 
        ///    Dim myGridColumn As DataGridColumnStyle
        ///    myGridColumn = DataGrid1.GridColumns(0)
        ///    ' Set the AlternatingBackColor to the color object.
        ///    myGridColumn.AlternatingBackColor = c 
        /// End Sub
        ///  
        ///  
        /// 
        ///  
        [SRCategory(SR.CatColors)]
        public virtual Color AlternatingBackColor {
            get {
                if (alternatingBackBrush != null) { 
                    return alternatingBackBrush.Color;
                } 
                DataGrid grid = DataGrid; 
                if (grid != null) {
                    return this.DataGridTableStyle.AlternatingBackColor; 
                }
                return System.Windows.Forms.DataGridTableStyle.defaultAlternatingBackBrush.Color;
            }
            set { 
                if (value != Color.Empty && alternatingBackBrush != null && value.Equals(alternatingBackBrush.Color)) {
                    return; 
                } 
                this.alternatingBackBrush = new SolidBrush(value);
                RaisePropertyChanged(EventArgs.Empty"AlternatingBackColor"); 
                Invalidate();
            }
        }
        */ 

        /* 
        ///  
        /// Indicates whether the 
        /// property should be persisted. 
        /// 
        /// 
        /// if the property
        ///    value has been changed from its default; otherwise, 
        /// .
        ///  
        ///  
        ///    You typically use this method only if you are either
        ///       creating a designer for the , or creating your own control 
        ///       incorporating the .
        /// You can use the  method to
        ///    determine whether the property value has changed from its default.
        ///  
        /// 
        internal bool ShouldSerializeAlternatingBackColor() { 
            return alternatingBackBrush != null; 
        }
        */ 

        /*
        /// 
        ///     
        ///       Resets the 
        ///       property to its default value. 
        ///     
        /// 
        ///  
        ///    
        ///       You typically use this method only if you are either creating a designer for
        ///       the , or creating your own control incorporating the
        ///    . 
        ///    
        ///     
        ///       You can use the  
        ///       method to determine whether the property value has changed from its default.
        ///     
        ///    
        ///       The OnPropertyChanged
        ///       event occurs when the property value changes.
        ///     
        /// 
        public void ResetAlternatingBackColor() { 
            if (alternatingBackBrush != null) { 
                this.alternatingBackBrush = null;
                RaisePropertyChanged(EventArgs.Empty"AlternatingBackColor"); 
                Invalidate();
            }
        }
        */ 

        /* 
        ///  
        ///    
        ///       Gets either the  or the  of 
        ///       a specified row.
        ///    
        /// 
        ///  
        ///    
        ///       A  that represents the background color. 
        ///     
        /// 
        ///  
        /// 
        /// 
        /// 
        public Color GetBackColor(int rowNum) { 
            DataGrid grid = DataGrid;
            if (rowNum % 2 == 1 && (grid != null && grid.LedgerStyle)) 
                return AlternatingBackColor; 
            else
                return BackColor; 
        }
        */

        ///  
        /// 
        ///    When overridden in a derived class, updates the value of a specified row with 
        ///       the given text. 
        /// 
        // PM team has reviewed and decided on naming changes already 
        [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly")]
        protected internal virtual void UpdateUI(CurrencyManager source, int rowNum, string displayText)
        {
        } 

        ///  
        ///  
        /// 
        ///     
        ///       [To Editor: I think this is going away.]
        ///    
        ///    
        ///       Gets or sets the background color of the column. 
        ///    
        ///  
        [Browsable(false)] 
        public AccessibleObject HeaderAccessibleObject {
            get { 
                if (headerAccessibleObject == null) {
                    headerAccessibleObject = CreateHeaderAccessibleObject();
                }
                return headerAccessibleObject; 
            }
        } 
 
        /// 
        ///  
        /// Gets or sets the  that determines the
        ///    attributes of data displayed by the .
        /// 
        [DefaultValue(null), Browsable(false), EditorBrowsable(EditorBrowsableState.Advanced)] 
        public virtual PropertyDescriptor PropertyDescriptor {
            get { 
                return propertyDescriptor; 
            }
            set { 
                if (propertyDescriptor != value) {
                    propertyDescriptor = value;
                    OnPropertyDescriptorChanged(EventArgs.Empty);
                    /* 
                    //
 
 
*/
                } 
            }
        }

        ///  
        [Browsable(false), EditorBrowsable(EditorBrowsableState.Advanced)]
        public event EventHandler PropertyDescriptorChanged { 
            add { 
                Events.AddHandler(EventPropertyDescriptor, value);
            } 
            remove {
                Events.RemoveHandler(EventPropertyDescriptor, value);
            }
        } 

        ///  
        ///  
        /// Gets the  control that the  belongs to.
        ///  
        /*
        protected virtual DataGrid DataGrid {
            get {
                DataGridTableStyle gridTable = DataGridTableStyle; 
                if (gridTable == null)
                    return null; 
                return gridTable.DataGrid; 
            }
        } 
        */

        protected virtual AccessibleObject CreateHeaderAccessibleObject() {
            return new DataGridColumnHeaderAccessibleObject(this); 
        }
 
        ///  
        /// 
        /// When overridden in a derived class, sets the  control that this column 
        ///    belongs to.
        /// 
        protected virtual void SetDataGrid(DataGrid value)
        { 
            SetDataGridInColumn(value);
        } 
 
        /// 
        ///  
        ///    
        ///       When overridden in a derived class,
        ///       sets the  for the column.
        ///     
        /// 
        protected virtual void SetDataGridInColumn(DataGrid value) { 
            // we need to set up the PropertyDescriptor 
            if (this.PropertyDescriptor == null && value != null)
            { 
                CurrencyManager lm = value.ListManager;
                if (lm == null) return;
                PropertyDescriptorCollection propCollection = lm.GetItemProperties();
                int propCount = propCollection.Count; 
                for (int i = 0; i < propCollection.Count; i++)
                { 
                    PropertyDescriptor prop = propCollection[i]; 
                    if (!typeof(IList).IsAssignableFrom(prop.PropertyType) && prop.Name.Equals(this.HeaderText))
                    { 
                        this.PropertyDescriptor = prop;
                        return;
                    }
                } 
            }
        } 
 
        internal void SetDataGridInternalInColumn(DataGrid value) {
            if (value == null || value.Initializing) 
                return;
            SetDataGridInColumn(value);
        }
 
        /// 
        ///  
        ///     
        ///       Gets the System.Windows.Forms.DataGridTableStyle for the column.
        ///     
        /// 
        [Browsable(false)]
        public virtual DataGridTableStyle DataGridTableStyle {
            get { 
                return dataGridTableStyle;
            } 
        } 

        internal void SetDataGridTableInColumn(DataGridTableStyle value, bool force) { 
            if (dataGridTableStyle != null && dataGridTableStyle.Equals(value) && !force)
                return;
            if (value != null) {
                if (value.DataGrid != null && !value.DataGrid.Initializing) { 
                    this.SetDataGridInColumn(value.DataGrid);
                } 
            } 
            dataGridTableStyle = value;
        } 

        /// 
        /// 
        ///     
        ///       Gets the height of the column's font.
        ///     
        ///  
        protected int FontHeight {
            get { 
                if (fontHeight != -1) {
                    return fontHeight;
                }
                else if (DataGridTableStyle!= null) { 
                    return DataGridTableStyle.DataGrid.FontHeight;
                } 
                else { 
                    return DataGridTableStyle.defaultFontHeight;
                } 
            }
        }

        ///  
        ///    
        ///       Indicates whether the Font property should be persisted. 
        ///     
        /// 
        private bool ShouldSerializeFont() { 
            return font != null;
        }

        ///  
        public event EventHandler FontChanged {
            add { 
            } 
            remove {
            } 
        }


        /* 
        /// 
        ///     
        ///       Gets or sets the foreground color of the column. 
        ///    
        ///  
        /// 
        ///    
        ///       A  that represents the foreground color. The
        ///       default is the foreground color of the  control. 
        ///    
        ///  
        ///  
        ///    
        ///       The OnPropertyChanged event occurs when the property value 
        ///       changes.
        ///    
        /// 
        ///  
        ///    
        ///       The following example sets the  property of 
        ///       a given . 
        ///    
        ///     
        /// Dim c As System.Drawing.Color
        /// Dim dgCol As DataGridColumnStyle
        /// c = System.Drawing.CadetBlue
        /// Set dgCol = DataGrid1.GridColumns(0) 
        /// dgCol.ForeColor = c
        ///        
        ///  
        /// 
        ///  
        /// 
        /// 
        public virtual Color ForeColor {
            get { 
                if (foreBrush != null) {
                    return foreBrush.Color; 
                } 
                DataGrid grid = DataGrid;
                if (grid != null) { 
                    return grid.ForeColor;
                }
                return DataGrid.defaultForeBrush.Color;
            } 
            set {
                if (value != Color.Empty && foreBrush != null && value.Equals(foreBrush.Color)) 
                    return; 
                this.foreBrush = new SolidBrush(value);
                RaisePropertyChanged(EventArgs.Empty"ForeColor"); 
                Invalidate();
            }
        }
 
        // used by the DataGridRow
        internal SolidBrush ForeBrush { 
            get { 
                if (foreBrush != null) {
                    return foreBrush; 
                }
                DataGrid grid = DataGrid;
                if (grid != null) {
                    return grid.ForeBrush; 
                }
                return DataGrid.defaultForeBrush; 
            } 
        }
        */ 

        /*
        /// 
        ///     
        ///       Indicates if the  property should be
        ///       persisted. 
        ///     
        /// 
        ///  
        ///    
        ///    if the property value has been changed from its
        ///       default; otherwise,  .
        ///     
        /// 
        ///  
        ///     
        ///       You typically use this method only if you are either creating a designer for
        ///       the , or creating your own control incorporating the 
        ///    .
        ///    
        /// 
        internal bool ShouldSerializeForeColor() { 
            return foreBrush != null;
        } 
        */ 

        /* 
        /// 
        ///    
        ///       Resets the  property to its default value.
        ///     
        /// 
        ///  
        ///     
        ///       You typically use this method if you are either creating a designer for
        ///       the , or creating your own control incorporating the 
        ///    .
        ///    
        ///    
        ///       You can use the  method to 
        ///       determine whether the property value has changed from its default.
        ///     
        ///     
        ///       The OnPropertyChanged event occurs when the property
        ///       value changes. 
        ///    
        /// 
        public void ResetForeColor() {
            if (foreBrush != null) { 
                foreBrush = null;
                RaisePropertyChanged(EventArgs.Empty"ForeColor"); 
                Invalidate(); 
            }
        } 
        */

        /// 
        ///  
        ///    
        ///       Gets or sets 
        ///       the text of the column header. 
        ///    
        ///  
        [
        Localizable(true),
        SRCategory(SR.CatDisplay)
        ] 
        public virtual string HeaderText {
            get { 
                return headerName; 
            }
            set { 
                if (value == null)
                    value = "";

                if (headerName.Equals(value)) 
                    return;
 
                headerName = value; 
                OnHeaderTextChanged(EventArgs.Empty);
                // we only invalidate columns that are visible ( ie, their propertyDescriptor is not null) 
                if (this.PropertyDescriptor != null)
                    Invalidate();
            }
        } 

        ///  
        public event EventHandler HeaderTextChanged { 
            add {
                Events.AddHandler(EventHeaderText, value); 
            }
            remove {
                Events.RemoveHandler(EventHeaderText, value);
            } 
        }
 
        ///  
        /// 
        ///    [To be supplied.] 
        /// 
        [
        Editor("System.Windows.Forms.Design.DataGridColumnStyleMappingNameEditor, " + AssemblyRef.SystemDesign, typeof(System.Drawing.Design.UITypeEditor)),
        Localizable(true), 
        DefaultValue("")
        ] 
        public string MappingName { 
            get {
                return mappingName; 
            }
            set {
                if (value == null)
                    value = ""; 
                if (mappingName.Equals(value))
                    return; 
                string originalMappingName = mappingName; 
                // this may throw
                mappingName = value; 
                try {
                    if (this.dataGridTableStyle != null)
                        this.dataGridTableStyle.GridColumnStyles.CheckForMappingNameDuplicates(this);
                } catch { 
                    mappingName = originalMappingName;
                    throw; 
                } 
                OnMappingNameChanged(EventArgs.Empty);
            } 
        }

        /// 
        public event EventHandler MappingNameChanged { 
            add {
                Events.AddHandler(EventMappingName, value); 
            } 
            remove {
                Events.RemoveHandler(EventMappingName, value); 
            }
        }

        ///  
        ///    
        ///       Indicates whether the System.Windows.Forms.DataGridColumnStyle.Header property should be 
        ///       persisted. 
        ///    
        ///  
        private bool ShouldSerializeHeaderText() {
            return(headerName.Length != 0);
        }
 
        /// 
        ///  
        ///     
        ///       Resets the System.Windows.Forms.DataGridColumnStyle.Header to its default value
        ///       ( ). 
        ///    
        /// 
        public void ResetHeaderText() {
            HeaderText = ""; 
        }
 
        ///  
        /// 
        ///    Gets or sets the text that is displayed when the column contains a null 
        ///       value.
        /// 
        [
        Localizable(true), 
        SRCategory(SR.CatDisplay)
        ] 
        public virtual string NullText { 
            get {
                return nullText; 
            }
            set {
                if (nullText != null && nullText.Equals(value))
                    return; 
                nullText = value;
                OnNullTextChanged(EventArgs.Empty); 
                Invalidate(); 
            }
        } 

        /// 
        public event EventHandler NullTextChanged {
            add { 
                Events.AddHandler(EventNullText, value);
            } 
            remove { 
                Events.RemoveHandler(EventNullText, value);
            } 
        }

        /// 
        ///  
        ///    Gets or sets a value indicating whether the data in the column cannot be edited.
        ///  
        [DefaultValue(false)] 
        public virtual bool ReadOnly {
            get { 
                return readOnly;
            }
            set {
                if (readOnly != value) { 
                    readOnly = value;
                    OnReadOnlyChanged(EventArgs.Empty); 
                } 
            }
        } 

        /// 
        public event EventHandler ReadOnlyChanged {
            add { 
                Events.AddHandler(EventReadOnly, value);
            } 
            remove { 
                Events.RemoveHandler(EventReadOnly, value);
            } 
        }

#if false
        ///  
        /// 
        ///     
        ///       Gets or sets a value indicating whether the column is visible. 
        ///    
        ///  
        [DefaultValue(true)]
        public virtual bool Visible {
            get {
                return visible; 
            }
            set { 
                if (visible == value) 
                    return;
                visible = value; 
                RaisePropertyChanged(EventArgs.Empty"Visible");
                Invalidate();
            }
        } 
#endif
 
        ///  
        /// 
        ///     
        ///       Gets or sets the width of the column.
        ///    
        /// 
        [ 
        SRCategory(SR.CatLayout),
        Localizable(true), 
        DefaultValue(100) 
        ]
        public virtual int Width { 
            get {
                return width;
            }
            set { 
                if (width != value) {
                    width = value; 
                    DataGrid grid = this.DataGridTableStyle == null ? null : DataGridTableStyle.DataGrid; 
                    if (grid != null) {
                        // rearrange the scroll bars 
                        grid.PerformLayout();

                        // force the grid to repaint
                        grid.InvalidateInside(); 
                    }
                    OnWidthChanged(EventArgs.Empty); 
                } 
            }
        } 

        /// 
        public event EventHandler WidthChanged {
            add { 
                Events.AddHandler(EventWidth, value);
            } 
            remove { 
                Events.RemoveHandler(EventWidth, value);
            } 
        }

        // =------------------------------------------------------------------
        // =        Methods 
        // =-----------------------------------------------------------------
 
        ///  
        /// 
        ///     
        ///       Suspends the painting of the column until the 
        ///       method is called.
        ///    
        ///  
        protected void BeginUpdate() {
            updating = true; 
        } 

        ///  
        /// 
        ///    
        ///       Resumes the painting of columns suspended by calling the
        ///     
        ///    method.
        ///  
        ///  
        protected void EndUpdate() {
            updating = false; 
            if (invalid) {
                invalid = false;
                Invalidate();
            } 
        }
 
        internal virtual bool WantArrows { 
            get {
                return false; 
            }
        }

 
        internal virtual string GetDisplayText(object value) {
            return value.ToString(); 
        } 

 	private void ResetNullText() { 
		NullText = SR.GetString(SR.DataGridNullText);
	}
		
 
        private bool ShouldSerializeNullText() {
            return (!SR.GetString(SR.DataGridNullText).Equals(nullText)); 
        } 

        ///  
        /// 
        ///    When overridden in a derived class,
        ///       gets the optimum width and height of the specified value.
        ///  
        protected internal abstract Size GetPreferredSize(Graphics g, object value);
 
        ///  
        /// 
        ///    Gets the minimum height of a row. 
        /// 
        protected internal abstract int GetMinimumHeight();

        ///  
        /// 
        ///    When 
        ///       overridden in a derived class, gets the height to be used in for automatically resizing columns. 
        /// 
        protected internal abstract int GetPreferredHeight(Graphics g, object value); 

        /// 
        /// 
        ///    Gets the value in the specified row from the specified 
        ///    System.Windows.Forms.ListManager.
        ///  
        // PM team has reviewed and decided on naming changes already 
        [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly")]
        protected internal virtual object GetColumnValueAtRow(CurrencyManager source, int rowNum) { 
            CheckValidDataSource(source);
            if (PropertyDescriptor == null) {
                throw new InvalidOperationException(SR.GetString(SR.DataGridColumnNoPropertyDescriptor));
            } 
            object value = PropertyDescriptor.GetValue(source[rowNum]);
            return value; 
        } 

        ///  
        /// 
        ///    Redraws the column and causes a paint
        ///       message to be sent to the control.
        ///  
        protected virtual void Invalidate() {
            if (updating) { 
                invalid = true; 
                return;
            } 
            DataGridTableStyle table = this.DataGridTableStyle;
            if (table != null)
                table.InvalidateColumn(this);
        } 

        ///  
        ///  
        /// Checks if the specified DataView is valid.
        ///  
        protected void CheckValidDataSource(CurrencyManager value) {
            if (value == null) {
                throw new ArgumentNullException("value", "DataGridColumnStyle.CheckValidDataSource(DataSource value), value == null");
            } 
            // the code may delete a gridColumn that was editing
            // in that case, we still have to push the value into the backEnd 
            // and we only need the propertyDescriptor to push the value. 
            // (take a look at gridEditAndDeleteEditColumn)
            // 
            // DataGridTableStyle myTable = this.DataGridTableStyle;
            PropertyDescriptor myPropDesc = this.PropertyDescriptor;
            if (myPropDesc == null) {
                throw new InvalidOperationException(SR.GetString(SR.DataGridColumnUnbound, HeaderText)); 
            }
 
#if false 
            DataTable myDataTable = myTable.DataTable;
            if (myDataColumn.Table != myDataTable) { 
                throw new InvalidOperationException(SR.GetString(SR.DataGridColumnDataSourceMismatch, Header));
            }

            /* FOR DEMO: [....]: DataGridColumnStyle::CheckValidDataSource: make the check better */ 
            if (((DataView) value.DataSource).Table == null) {
                throw new InvalidOperationException(SR.GetString(SR.DataGridColumnNoDataTable, Header)); 
            } 
            else {
                /* FOR DEMO: [....]: DataGridColumnStyle::CheckValidDataSource: make the check better */ 
                if (!myTable.DataTable.Equals(((DataView) value.DataSource).Table)) {
                    throw new InvalidOperationException(SR.GetString(SR.DataGridColumnNoDataSource, Header, myTable.DataTable.TableName));
                }
            } 
#endif // false
        } 
 
        /// 
        ///  
        ///    
        ///       When overridden in a derived class, initiates a
        ///       request to interrrupt an edit procedure.
        ///     
        /// 
        // PM team has reviewed and decided on naming changes already 
        [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly")] 
        protected internal abstract void Abort(int rowNum);
 
        /// 
        /// 
        ///    When overridden in a derived class, inititates a request to complete an
        ///       editing procedure. 
        /// 
        // PM team has reviewed and decided on naming changes already 
        [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly")] 
        protected internal abstract bool Commit(CurrencyManager dataSource, int rowNum);
 
        /// 
        /// 
        ///    When overridden in a deriving class, prepares a cell for editing.
        ///  
        // PM team has reviewed and decided on naming changes already
        [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly")] 
        protected internal virtual void Edit(CurrencyManager source, 
                                             int rowNum,
                                             Rectangle bounds, 
                                             bool readOnly) {
            Edit(source, rowNum, bounds, readOnly, null, true);
        }
 
        /// 
        ///  
        ///    Prepares the 
        ///       cell for editing, passing the specified , row number, , argument
        ///       indicating whether the column is read-only, and the 
        ///       text to display in the new control.
        /// 
        // PM team has reviewed and decided on naming changes already
        [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly")] 
        protected internal virtual void Edit(CurrencyManager source,
                                   int rowNum, 
                                   Rectangle bounds, 
                                   bool readOnly,
                                   string displayText) { 
            Edit(source, rowNum, bounds, readOnly, displayText, true);
        }

        ///  
        /// 
        ///    When overridden in a deriving class, prepares a cell for editing. 
        ///  
        // PM team has reviewed and decided on naming changes already
        [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly")] 
        protected internal abstract void Edit(CurrencyManager source,
                                    int rowNum,
                                    Rectangle bounds,
                                    bool readOnly, 
                                    string displayText,
                                    bool cellIsVisible); 
 
        /// 
        ///  
        /// 
        ///    Indicates whether the a mouse down event occurred at the specified row, at
        ///       the specified x and y coordinates.
        ///  
        internal virtual bool MouseDown(int rowNum, int x, int y) {
            return false; 
        } 

        // this function mainly serves Alt0 functionality 
        /// 
        /// 
        /// When overriden in a derived class, enters a 
        /// into the column. 
        /// 
        protected internal virtual void EnterNullValue() { 
        } 

        ///  
        /// 
        ///    
        ///       Provides a handler for determining which key was pressed,
        ///       and whether to process it. 
        ///    
        ///  
        internal virtual bool KeyPress(int rowNum, Keys keyData) { 
            // if this is read only then do not do anything
            if (this.ReadOnly || (this.DataGridTableStyle != null && this.DataGridTableStyle.DataGrid != null && this.DataGridTableStyle.DataGrid.ReadOnly)) 
                return false;
            if (keyData == (Keys.Control | Keys.NumPad0) || keyData == (Keys.Control| Keys.D0)) {
                EnterNullValue();
                return true; 
            }
            return false; 
        } 

        // will cause the edit control to become invisible when 
        // the user navigates to a focused relation child
        /// 
        /// 
        ///    When overridden in a derived class, directs the column to concede focus with an appropriate action. 
        /// 
        protected internal virtual void ConcedeFocus() { 
        } 

        ///  
        /// 
        /// Paints the a  with the specified ,
        /// , System.Windows.Forms.CurrencyManager, and row number.
        ///  
        // PM team has reviewed and decided on naming changes already
        [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly")] 
        protected internal abstract void Paint(Graphics g, Rectangle bounds, CurrencyManager source, int rowNum); 

        ///  
        /// 
        ///    When overridden in a derived class,
        ///       paints a  with the specified , , see Rectangle, row number, and
        ///       alignment. 
        /// 
        // PM team has reviewed and decided on naming changes already 
        [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly")] 
        protected internal abstract void Paint(Graphics g, Rectangle bounds, CurrencyManager source, int rowNum, bool alignToRight);
 
        /// 
        /// 
        ///    
        ///       Paints a  with the specified , , see System.Data.DataView, row number, background color, foreground color, and alignment. 
        ///    
        ///  
        // PM team has reviewed and decided on naming changes already 
        [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly")]
        protected internal virtual void Paint(Graphics g, Rectangle bounds, CurrencyManager source, int rowNum, 
                                    Brush backBrush, Brush foreBrush, bool alignToRight) {
            Paint(g, bounds, source, rowNum, alignToRight);
        }
 
        private void OnPropertyDescriptorChanged(EventArgs e) {
            EventHandler eh = Events[EventPropertyDescriptor] as EventHandler; 
            if (eh != null) 
                eh(this, e);
        } 
        private void OnAlignmentChanged(EventArgs e) {
            EventHandler eh = Events[EventAlignment] as EventHandler;
            if (eh != null)
                eh(this, e); 
        }
        private void OnHeaderTextChanged(EventArgs e) { 
            EventHandler eh = Events[EventHeaderText] as EventHandler; 
            if (eh != null)
                eh(this, e); 
        }
        private void OnMappingNameChanged(EventArgs e) {
            EventHandler eh = Events[EventMappingName] as EventHandler;
            if (eh != null) 
                eh(this, e);
        } 
        private void OnReadOnlyChanged(EventArgs e) { 
            EventHandler eh = Events[EventReadOnly] as EventHandler;
            if (eh != null) 
                eh(this, e);
        }
        private void OnNullTextChanged(EventArgs e) {
            EventHandler eh = Events[EventNullText] as EventHandler; 
            if (eh != null)
                eh(this, e); 
        } 
        private void OnWidthChanged(EventArgs e) {
            EventHandler eh = Events[EventWidth] as EventHandler; 
            if (eh != null)
                eh(this, e);
        }
 
        /// 
        ///  
        ///    Sets 
        ///       the value in a specified row
        ///       with the value from a specified see DataView. 
        /// 
        // PM team has reviewed and decided on naming changes already
        [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly")]
        protected internal virtual void SetColumnValueAtRow(CurrencyManager source, int rowNum, object value) { 
            CheckValidDataSource(source);
 
            if (source.Position != rowNum) 
                throw new ArgumentException(SR.GetString(SR.DataGridColumnListManagerPosition), "rowNum");
            if (source[rowNum] is IEditableObject) 
                ((IEditableObject)source[rowNum]).BeginEdit();
            this.PropertyDescriptor.SetValue(source[rowNum], value);
        }
 
        /// 
        internal protected virtual void ColumnStartedEditing(Control editingControl) { 
            this.DataGridTableStyle.DataGrid.ColumnStartedEditing(editingControl); 
        }
 
        /// 
        /// 
        void IDataGridColumnStyleEditingNotificationService.ColumnStartedEditing(Control editingControl) {
            this.ColumnStartedEditing(editingControl); 
        }
 
 
        /// 
        protected internal virtual void ReleaseHostedControl() { 
        }

        /// 
        ///  
        protected class CompModSwitches {
            private static TraceSwitch dgEditColumnEditing; 
 
            /// 
            public static TraceSwitch DGEditColumnEditing { 
                get {
                    if (dgEditColumnEditing == null) {
                        dgEditColumnEditing = new TraceSwitch("DGEditColumnEditing", "Editing related tracing");
                    } 
                    return dgEditColumnEditing;
                } 
            } 
        }
 

        /// 
        /// 
        ///    [To be supplied.] 
        /// 
        [System.Runtime.InteropServices.ComVisible(true)] 
        protected class DataGridColumnHeaderAccessibleObject : AccessibleObject { 
            DataGridColumnStyle owner = null;
 
            /// 
            /// 
            ///    [To be supplied.]
            ///  
            public DataGridColumnHeaderAccessibleObject(DataGridColumnStyle owner) : this() {
                Debug.Assert(owner != null, "DataGridColumnHeaderAccessibleObject must have a valid owner DataGridColumn"); 
                this.owner = owner; 

            } 

            /// 
            /// 
            ///    [To be supplied.] 
            /// 
            public DataGridColumnHeaderAccessibleObject() : base() { 
            } 

            ///  
            /// 
            ///    [To be supplied.]
            /// 
            public override Rectangle Bounds { 
                get {
                    // we need to get the width and the X coordinate of this column on the screen 
                    // we can't just cache this, cause the column may be moved in the collection 
                    if (this.owner.PropertyDescriptor == null)
                        return Rectangle.Empty; 

                    DataGrid dg = this.DataGrid;
                    if (dg.DataGridRowsLength == 0)
                        return Rectangle.Empty; 

                    // we need to find this column's offset in the gridColumnCollection... 
                    GridColumnStylesCollection cols = this.owner.dataGridTableStyle.GridColumnStyles; 
                    int offset = -1;
                    for (int i = 0; i < cols.Count; i++) 
                        if (cols[i] == this.owner) {
                            offset = i;
                            break;
                        } 
                    Debug.Assert(offset >= 0, "this column must be in a collection, otherwise its bounds are useless");
                    Rectangle rect = dg.GetCellBounds(0, offset); 
                    // now add the Y coordinate of the datagrid.Layout.Data. it should be the same as 
                    // dataGrid.Layout.ColumnHeaders
                    rect.Y = dg.GetColumnHeadersRect().Y; 
                    return dg.RectangleToScreen(rect);
                }
            }
 
            /// 
            ///  
            ///    [To be supplied.] 
            /// 
            public override string Name { 
                get {
                    return Owner.headerName;
                }
            } 

            ///  
            ///  
            ///    [To be supplied.]
            ///  
            protected DataGridColumnStyle Owner {
                get {
                    return owner;
                } 
            }
 
            ///  
            /// 
            ///    [To be supplied.] 
            /// 
            public override AccessibleObject Parent {
                [SecurityPermission(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)]
                get { 
                    return DataGrid.AccessibilityObject;
                } 
            } 

            private DataGrid DataGrid { 
                get {
                    return owner.dataGridTableStyle.dataGrid;
                }
            } 

            ///  
            ///  
            ///    [To be supplied.]
            ///  
            public override AccessibleRole Role {
                get {
                    return AccessibleRole.ColumnHeader;
                } 
            }
 
            ///  
            /// 
            ///    [To be supplied.] 
            /// 
            [SecurityPermission(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)]
            public override AccessibleObject Navigate(AccessibleNavigation navdir) {
                switch (navdir) { 
                    case AccessibleNavigation.Right:
                    case AccessibleNavigation.Next: 
                    case AccessibleNavigation.Down: 
                        return Parent.GetChild(1 + Owner.dataGridTableStyle.GridColumnStyles.IndexOf(Owner) + 1);
                    case AccessibleNavigation.Up: 
                    case AccessibleNavigation.Left:
                    case AccessibleNavigation.Previous:
                        return Parent.GetChild(1 + Owner.dataGridTableStyle.GridColumnStyles.IndexOf(Owner) - 1);
 
                }
 
                return null; 

            } 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.


                        

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