ContextMenu.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / ContextMenu.cs / 1 / ContextMenu.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Windows.Forms { 
 
    using Microsoft.Win32;
    using System; 
    using System.ComponentModel;
    using System.Diagnostics;
    using System.Drawing;
    using System.Runtime.InteropServices; 
    using System.Runtime.Remoting;
    using System.Security; 
    using System.Security.Permissions; 

    ///  
    /// 
    ///     This class is used to put context menus on your form and show them for
    ///     controls at runtime.  It basically acts like a regular Menu control,
    ///     but can be set for the ContextMenu property that most controls have. 
    /// 
    [ 
    DefaultEvent("Popup"), 
    ]
    public class ContextMenu : Menu { 

        private EventHandler onPopup;
        private EventHandler onCollapse;
        internal Control sourceControl; 

        private RightToLeft rightToLeft = System.Windows.Forms.RightToLeft.Inherit; 
 
        /// 
        ///  
        ///     Creates a new ContextMenu object with no items in it by default.
        /// 
        public ContextMenu()
            : base(null) { 
        }
 
        ///  
        /// 
        ///     Creates a ContextMenu object with the given MenuItems. 
        /// 
        public ContextMenu(MenuItem[] menuItems)
            : base(menuItems) {
        } 

        ///  
        ///  
        ///     The last control that was acted upon that resulted in this context
        ///     menu being displayed. 
        ///     VSWHIDBEY 426099 - add demand for AllWindows.
        /// 
        [
        Browsable(false), 
        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden),
        SRDescription(SR.ContextMenuSourceControlDescr) 
        ] 
        public Control SourceControl {
            [UIPermission(SecurityAction.Demand, Window=UIPermissionWindow.AllWindows)] 
            get {
                return sourceControl;
            }
        } 

        ///  
        ///  
        ///    [To be supplied.]
        ///  
        [SRDescription(SR.MenuItemOnInitDescr)]
        public event EventHandler Popup {
            add {
                onPopup += value; 
            }
            remove { 
                onPopup -= value; 
            }
        } 

        /// 
        /// 
        ///    Fires when the context menu collapses. 
        /// 
        [SRDescription(SR.ContextMenuCollapseDescr)] 
        public event EventHandler Collapse { 
            add {
                onCollapse += value; 
            }
            remove {
                onCollapse -= value;
            } 
        }
 
        ///  
        /// 
        ///     This is used for international applications where the language 
        ///     is written from RightToLeft. When this property is true,
        ///     text alignment and reading order will be from right to left.
        /// 
        // VSWhidbey 164244: Add a DefaultValue attribute so that the Reset context menu becomes 
        // available in the Property Grid but the default value remains No.
        [ 
        Localizable(true), 
        DefaultValue(RightToLeft.No),
        SRDescription(SR.MenuRightToLeftDescr) 
        ]
        public virtual RightToLeft RightToLeft {
            get {
                if (System.Windows.Forms.RightToLeft.Inherit == rightToLeft) { 
                    if (sourceControl != null) {
                        return ((Control)sourceControl).RightToLeft; 
                    } 
                    else {
                        return RightToLeft.No; 
                    }
                }
                else {
                    return rightToLeft; 
                }
            } 
            set { 

                //valid values are 0x0 to 0x2. 
                if (!ClientUtils.IsEnumValid(value, (int)value, (int)RightToLeft.No, (int)RightToLeft.Inherit)){
                    throw new InvalidEnumArgumentException("RightToLeft", (int)value, typeof(RightToLeft));
                }
                if (RightToLeft != value) { 
                    rightToLeft = value;
                    UpdateRtl((value == System.Windows.Forms.RightToLeft.Yes)); 
                } 

            } 
        }

        internal override bool RenderIsRightToLeft {
            get { 
                return (rightToLeft == System.Windows.Forms.RightToLeft.Yes);
            } 
        } 
        /// 
        ///  
        ///     Fires the popup event
        /// 
        protected internal virtual void OnPopup(EventArgs e) {
            if (onPopup != null) { 
                onPopup(this, e);
            } 
        } 

        ///  
        /// 
        ///     Fires the collapse event
        /// 
        protected internal virtual void OnCollapse(EventArgs e) { 
            if (onCollapse != null) {
                onCollapse(this, e); 
            } 
        }
 
        /// 
        /// 
        /// 
        ///  
        [
            System.Security.Permissions.SecurityPermissionAttribute(System.Security.Permissions.SecurityAction.LinkDemand, Flags=System.Security.Permissions.SecurityPermissionFlag.UnmanagedCode), 
            System.Security.Permissions.SecurityPermissionAttribute(System.Security.Permissions.SecurityAction.InheritanceDemand, Flags=System.Security.Permissions.SecurityPermissionFlag.UnmanagedCode) 
        ]
        protected internal virtual bool ProcessCmdKey(ref Message msg, Keys keyData, Control control) { 
            sourceControl = control;
            return ProcessCmdKey(ref msg, keyData);
        }
 
        private void ResetRightToLeft() {
        	RightToLeft = RightToLeft.No;	 
        } 

        ///  
        /// 
        ///     Returns true if the RightToLeft should be persisted in code gen.
        /// 
        internal virtual bool ShouldSerializeRightToLeft() { 
            if (System.Windows.Forms.RightToLeft.Inherit == rightToLeft) {
                return false; 
            } 
            return true;
        } 

        /// 
        /// 
        ///     Displays the context menu at the specified position.  This method 
        ///     doesn't return until the menu is dismissed.
        ///  
        public void Show(Control control, Point pos) { 
            Show(control, pos, NativeMethods.TPM_VERTICAL | NativeMethods.TPM_RIGHTBUTTON);
        } 

        /// 
        /// 
        ///     Displays the context menu at the specified position.  This method 
        ///     doesn't return until the menu is dismissed.
        ///  
        public void Show(Control control, Point pos, LeftRightAlignment alignment)  { 

            // This code below looks wrong but it's correct. 
            // WinForms Left alignment means we want the menu to show up left of the point it is invoked from.
            // We specify TPM_RIGHTALIGN which tells win32 to align the right side of this
            // menu with the point (which aligns it Left visually)
            if (alignment == LeftRightAlignment.Left) { 
                Show(control, pos, NativeMethods.TPM_VERTICAL | NativeMethods.TPM_RIGHTBUTTON | NativeMethods.TPM_RIGHTALIGN);
            } 
            else { 
                Show(control, pos, NativeMethods.TPM_VERTICAL | NativeMethods.TPM_RIGHTBUTTON | NativeMethods.TPM_LEFTALIGN);
            } 
        }

        private void Show(Control control, Point pos, int flags) {
            if (control == null) 
                throw new ArgumentNullException("control");
 
            if (!control.IsHandleCreated || !control.Visible) 
                throw new ArgumentException(SR.GetString(SR.ContextMenuInvalidParent), "control");
 
            sourceControl = control;

            OnPopup(EventArgs.Empty);
            pos = control.PointToScreen(pos); 
            SafeNativeMethods.TrackPopupMenuEx(new HandleRef(this, Handle),
                flags, 
                pos.X, 
                pos.Y,
                new HandleRef(control, control.Handle), 
                null);
        }

    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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ContextMenu.cs source code in C# .NET

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