mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/DialogWindow.cs

   1 //----------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //----------------------------------------------------------------
   4
   5 namespace System.Activities.Presentation
   6 {
   7     using System.Windows;
   8     using System.Activities.Presentation.View;
   9     using System.Windows.Interop;
  10     using System.Windows.Input;
  11     using System.ComponentModel;
  12     using Microsoft.Tools.Common;
  13
  14     internal class DialogWindow : Window
  15     {
  16         public static readonly DependencyProperty ContextProperty =
  17             DependencyProperty.Register("Context",
  18             typeof(EditingContext),
  19             typeof(DialogWindow));
  20
  21         string helpKeyword = HelpKeywords.HomePage;
  22
  23         public EditingContext Context
  24         {
  25             get { return (EditingContext)GetValue(ContextProperty); }
  26             set { SetValue(ContextProperty, value); }
  27         }
  28
  29         protected string HelpKeyword
  30         {
  31             get
  32             {
  33                 return this.helpKeyword;
  34             }
  35             set
  36             {
  37                 this.helpKeyword = value;
  38             }
  39         }
  40
  41         protected override void OnSourceInitialized(EventArgs e)
  42         {
  43             base.OnSourceInitialized(e);
  44
  45             this.HideMinMaxButton();
  46             this.ShowContextHelpButton();
  47             this.HideIcon();
  48             this.AddWindowsHook(OnHookedWindowMessage);
  49             this.CommandBindings.Add(new CommandBinding(ApplicationCommands.Help, new ExecutedRoutedEventHandler(OnHelpExecuted)));
  50             this.Closing += new CancelEventHandler(OnWindowClosing);
  51         }
  52
  53         static IntPtr OnHookedWindowMessage(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
  54         {
  55             if (msg == Win32Interop.WM_SYSCOMMAND && wParam.ToInt64() == (long)Win32Interop.SC_CONTEXTHELP)
  56             {
  57                 var rootVisual = HwndSource.FromHwnd(hwnd).RootVisual;
  58                 var focusedElement = FocusManager.GetFocusedElement(rootVisual);
  59                 if (focusedElement == null)
  60                 {
  61                     focusedElement = rootVisual as IInputElement;
  62                 }
  63                 ApplicationCommands.Help.Execute(null, focusedElement);
  64                 handled = true;
  65             }
  66
  67             // According to MSDN, zero should be returned after handling WM_SYSCOMMAND.
  68             // If this message is unhandled, it's still safe to return zero
  69             // because WPF framework (HwndSource) will return zero anyway if the
  70             // message is unhandled.
  71             return IntPtr.Zero;
  72         }
  73
  74         void OnWindowClosing(object sender, CancelEventArgs e)
  75         {
  76             // Note: Do NOT remove the hook if the close operation needs to be canceled.
  77             this.RemoveWindowsHook(OnHookedWindowMessage);
  78         }
  79
  80         void OnHelpExecuted(Object sender, ExecutedRoutedEventArgs e)
  81         {
  82             if (this.Context != null)
  83             {
  84                 IIntegratedHelpService help = this.Context.Services.GetService<IIntegratedHelpService>();
  85                 if (help != null)
  86                 {
  87                     help.ShowHelpFromKeyword(this.helpKeyword);
  88                     return;
  89                 }
  90             }
  91             System.Diagnostics.Process.Start(SR.DefaultHelpUrl);
  92         }
  93     }
  94 }