WindowInteractionStateTracker.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 / wpf / src / UIAutomation / UIAutomationClient / MS / Internal / Automation / WindowInteractionStateTracker.cs / 1305600 / WindowInteractionStateTracker.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: Class used to track new UI appearing and make sure any events 
// are propogated to that new UI.
// 
// History:
//  01/05/2005 : Created
//
//--------------------------------------------------------------------------- 

using System; 
using System.Globalization; 
using System.Text;
using System.Windows.Automation; 
using System.Diagnostics;
using MS.Win32;

namespace MS.Internal.Automation 
{
    // Class used to track new UI appearing and make sure any events 
    // are propogated to that new UI. 
    internal class WindowInteractionStateTracker : WinEventWrap
    { 
        //-----------------------------------------------------
        //
        //  Constructors
        // 
        //-----------------------------------------------------
 
        #region Constructors 

        internal WindowInteractionStateTracker() 
            : base(new int[] { NativeMethods.EVENT_OBJECT_STATECHANGE })
        {
            // Intentionally not setting the callback for the base WinEventWrap since the WinEventProc override
            // in this class calls RaiseEventInThisClientOnly to actually raise the event to the client. 
        }
 
        #endregion Constructors 

 
        //------------------------------------------------------
        //
        //  Internal Methods
        // 
        //-----------------------------------------------------
 
        #region Internal Methods 

        internal override void WinEventProc(int eventId, IntPtr hwnd, int idObject, int idChild, uint eventTime) 
        {
            // ignore any event not pertaining directly to the window
            if (idObject != UnsafeNativeMethods.OBJID_WINDOW)
            { 
                return;
            } 
 
            // Ignore if this is a bogus hwnd (shouldn't happen)
            if (hwnd == IntPtr.Zero) 
            {
                return;
            }
 
            OnStateChange(hwnd, idObject, idChild);
        } 
 
        #endregion Internal Methods
 

        //------------------------------------------------------
        //
        //  Private Methods 
        //
        //------------------------------------------------------ 
 
        #region Private Methods
 
        private void OnStateChange(IntPtr hwnd, int idObject, int idChild)
        {
            NativeMethods.HWND nativeHwnd = NativeMethods.HWND.Cast(hwnd);
 
            // Ignore windows that have been destroyed
            if (!SafeNativeMethods.IsWindow(nativeHwnd)) 
            { 
                return;
            } 

            AutomationElement rawEl = AutomationElement.FromHandle(hwnd);

            try 
            {
                rawEl.GetCurrentPattern(WindowPattern.Pattern); 
            } 
            catch (InvalidOperationException)
            { 
                // Only raise this event for elements with the WindowPattern.
                return;
            }
 
            Object windowInteractionState = rawEl.GetPatternPropertyValue(WindowPattern.WindowInteractionStateProperty, false);
 
            // if has no state value just return 
            if (!(windowInteractionState is WindowInteractionState))
            { 
                return;
            }

            WindowInteractionState state = (WindowInteractionState)windowInteractionState; 

            // Filter... avoid duplicate events 
            if (hwnd == _lastHwnd && state == _lastState) 
            {
                return; 
            }

            AutomationPropertyChangedEventArgs e = new AutomationPropertyChangedEventArgs(
                                        WindowPattern.WindowInteractionStateProperty, 
                                        hwnd == _lastHwnd ? _lastState : WindowInteractionState.Running,
                                        state); 
 
            ClientEventManager.RaiseEventInThisClientOnly(AutomationElement.AutomationPropertyChangedEvent, rawEl, e);
 
            // save the last hwnd/rect for filtering out duplicates
            _lastHwnd = hwnd;
            _lastState = state;
        } 

        #endregion Private Methods 
 

        //----------------------------------------------------- 
        //
        //  Private Fields
        //
        //------------------------------------------------------ 

        #region Private Fields 
 
        private WindowInteractionState _lastState;      // keep track of last interaction state
        private IntPtr _lastHwnd;                       // and hwnd for dup checking 

        #endregion Private Fields
    }
} 

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

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