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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
// Description: Class used to track context menus appearing
using System;
using System.Text;
using System.Windows.Automation;
using System.Diagnostics;
using MS.Win32;
namespace MS.Internal.Automation
{
internal delegate void MenuHandler( AutomationElement rawEl, bool menuHasOpened );
// MenuOpened - Class used to track context menus appearing
internal class MenuTracker : WinEventWrap
{
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
#region Constructors
internal MenuTracker(MenuHandler newHandler)
: base(new int[] {NativeMethods.EVENT_SYSTEM_MENUPOPUPSTART, NativeMethods.EVENT_SYSTEM_MENUPOPUPEND})
{
AddCallback(newHandler);
}
#endregion Constructors
//------------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
#region Internal Methods
internal override void WinEventProc(int eventId, IntPtr hwnd, int idObject, int idChild, uint eventTime)
{
AutomationElement rawEl = null;
bool menuHasOpened = eventId == NativeMethods.EVENT_SYSTEM_MENUPOPUPSTART;
// Only create a raw element wrapper if the menu has popped up. Send a
// null element for menu closed (the element isn't available anymore).
// If there is any requirement to provide information on what
// menu element has closed, client code can track menu opened and rely
// on the following menu closed event to be that menu element.
if( menuHasOpened )
{
// Ignore if this is a bogus hwnd (shouldn't happen)
if( hwnd == IntPtr.Zero )
return;
NativeMethods.HWND nativeHwnd = NativeMethods.HWND.Cast( hwnd );
if( !SafeNativeMethods.IsWindow( nativeHwnd ) )
return;
// Filter... send events for visible hwnds only
if( !SafeNativeMethods.IsWindowVisible( nativeHwnd ) )
return;
rawEl = AutomationElement.FromHandle( hwnd );
}
// Do callback. This handler is called due to a WinEvent on the client. The handler
// is going to hand off the work of calling out to the client code to another thread
// via a queue so it is safe to do this callback w/in the lock.
object [] handlers = GetHandlers();
Debug.Assert(handlers.Length <= 1, "handlers.Length");
if( handlers.Length > 0 )
( ( MenuHandler )handlers[0] )( rawEl, menuHasOpened );
}
#endregion Internal Methods
}
}
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