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/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / Tools / System.Activities.Presentation / System / Activities / Presentation / Hosting / WindowHelperService.cs / 1482484 / WindowHelperService.cs
//---------------------------------------------------------------- // Copyright (c) Microsoft Corporation. All rights reserved. //--------------------------------------------------------------- namespace System.Activities.Presentation.Hosting { using System; using System.Windows; using System.Windows.Interop; using System.Runtime; using System.Diagnostics.CodeAnalysis; using System.Activities.Presentation.View; public delegate void WindowMessage(int msgId, IntPtr parameter1, IntPtr parameter2 ); [Fx.Tag.XamlVisible(false)] public class WindowHelperService { HwndSource hwndSource; WindowMessage listeners; [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", Justification = "hwnd is a well known name.")] public WindowHelperService(IntPtr hwnd) { this.ParentWindowHwnd = hwnd; } [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", Justification = "hwnd is a well known name.")] public IntPtr ParentWindowHwnd { get; private set; } internal FrameworkElement View { get; set; } public bool TrySetWindowOwner(DependencyObject source, Window target) { bool result = false; Fx.Assert(source != null, "Source element cannot be null"); Fx.Assert(target != null, "Target window cannot be null"); if (null != source && null != target) { //try the easy way first Window owner = Window.GetWindow(source); if (null != owner) { target.Owner = owner; result = true; } //no - it didn't work else { IntPtr ownerHwnd = Win32Interop.GetActiveWindow(); if (ownerHwnd == IntPtr.Zero) { ownerHwnd = this.ParentWindowHwnd; } WindowInteropHelper interopHelper = new WindowInteropHelper(target); interopHelper.Owner = ownerHwnd; result = true; } } return result; } public bool RegisterWindowMessageHandler(WindowMessage callback) { bool result = true; if (null == callback) { throw FxTrace.Exception.AsError(new ArgumentNullException("callback")); } //if there are no other callbacks registered - create initial multicast delegate //and hookup message processing if (null == this.listeners) { this.listeners = (WindowMessage)Delegate.Combine(callback); this.HookupMessageProcessing(); } //otherwise, check if callback is not in the list already else { Delegate[] initial = this.listeners.GetInvocationList(); //if it isn't - add it to callback list if (-1 == Array.IndexOf(initial, callback)) { Delegate[] combined = new Delegate[initial.Length + 1]; combined[initial.Length] = callback; Array.Copy(initial, combined, initial.Length); this.listeners = (WindowMessage)Delegate.Combine(combined); } else { result = false; } } return result; } public bool UnregisterWindowMessageHandler(WindowMessage callback) { bool result = false; if (null == callback) { throw FxTrace.Exception.AsError(new ArgumentNullException("callback")); } //if there are any callbacks if (null != this.listeners) { Delegate[] list = this.listeners.GetInvocationList(); //check if given delegate belongs to the list if (-1 != Array.IndexOf (list, callback)) { //if list contained 1 element - there is nobody listening for events - remove hook if (list.Length == 1) { this.hwndSource.RemoveHook(new HwndSourceHook(OnMessage)); } //yes - remove it this.listeners = (WindowMessage)Delegate.Remove(this.listeners, callback); result = true; } } if (!result) { System.Diagnostics.Debug.WriteLine("UnregisterWindowMessageHandler - callback not in list"); } return result; } void HookupMessageProcessing() { //try to create hwnd source object if (null == this.hwndSource) { //first - try to create it using ParentWindow handle if (IntPtr.Zero != this.ParentWindowHwnd) { this.hwndSource = HwndSource.FromHwnd(this.ParentWindowHwnd); } //if didn't succeed - (either handle is null or we are hosted in [....] app) //try to create hwnd source out of designer's view if (null == this.hwndSource) { this.hwndSource = HwndSource.FromVisual(this.View) as HwndSource; } } Fx.Assert(null != this.hwndSource, "HwndSource should not be null!"); if (null != this.hwndSource) { //register for event notifications this.hwndSource.AddHook(new HwndSourceHook(OnMessage)); } } IntPtr OnMessage(IntPtr hwnd, int msgId, IntPtr wParam, IntPtr lParam, ref bool handled) { //notify all listeners about window message this.listeners(msgId, wParam, lParam); return IntPtr.Zero; } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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