mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/Base/Core/Internal/PropertyEditing/Automation/PropertyInspectorAutomationPeer.cs

   1 //----------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //----------------------------------------------------------------
   4 namespace System.Activities.Presentation.Internal.PropertyEditing.Automation
   5 {
   6     using System;
   7     using System.Collections.Generic;
   8     using System.Windows.Automation.Peers;
   9     using System.Windows.Controls;
  10     using System.Windows;
  11
  12     using System.Activities.Presentation;
  13     using System.Activities.Presentation.Internal.Properties;
  14     using System.Windows.Input;
  15
  16     // <summary>
  17     // AutomationPeer for PropertyInspector
  18     // </summary>
  19     internal class PropertyInspectorAutomationPeer : UIElementAutomationPeer
  20     {
  21
  22         private PropertyInspector _inspector;
  23
  24         // Current list of children automation peers.
  25         private List<AutomationPeer> _children;
  26
  27         public PropertyInspectorAutomationPeer(PropertyInspector owner)
  28             : base(owner)
  29         {
  30             if (owner == null)
  31             {
  32                 throw FxTrace.Exception.ArgumentNull("owner");
  33             }
  34
  35             _inspector = owner;
  36         }
  37
  38         // <summary>
  39         // Gets a list of AutomationPeers that contains the following:
  40         //     Type text box
  41         //     Name text box
  42         //     List of CategoryContainerAutomationPeers
  43         // </summary>
  44         // <returns></returns>
  45         protected override List<AutomationPeer> GetChildrenCore()
  46         {
  47             // If children list is not null and contains AutomationPeer that implements IAutomationFocusChangedEventSource
  48             // Then, unhook the automation focus events before clearing the list
  49             // Else, create a new one.
  50             if (_children != null)
  51             {
  52                 foreach (AutomationPeer peer in _children)
  53                 {
  54                     IAutomationFocusChangedEventSource unhookEventPeer = peer as IAutomationFocusChangedEventSource;
  55                     if (unhookEventPeer != null)
  56                     {
  57                         unhookEventPeer.UnloadEventHook();
  58                     }
  59                 }
  60                 _children.Clear();
  61             }
  62             else
  63             {
  64                 _children = new List<AutomationPeer>();
  65             }
  66             _children.Add(new TextBlockAutomationPeer(_inspector.SelectionTypeLabel));
  67             _children.Add(new UIElementAutomationPeer(_inspector.PropertyToolBar));
  68             _children.Add(new InfoTextBlockAutomationPeer(_inspector.UninitializedLabel));
  69             _children.Add(new InfoTextBlockAutomationPeer(_inspector.NoSearchResultsLabel));
  70             _children.Add(new CategoryListAutomationPeer(_inspector.CategoryList));
  71
  72             return _children;
  73         }
  74
  75         protected override Point GetClickablePointCore()
  76         {
  77             // return a point that, when clicked, selects the grid without selecting
  78             // any of the rows
  79             return this.Owner.PointToScreen(new Point(10, 10));
  80         }
  81
  82         protected override string GetHelpTextCore()
  83         {
  84             return Resources.PropertyEditing_PropertyInspectorAutomationPeerHelp;
  85         }
  86
  87         protected override string GetNameCore()
  88         {
  89             return Resources.PropertyEditing_PropertyInspector;
  90         }
  91
  92         protected override string GetClassNameCore()
  93         {
  94             return typeof(PropertyInspector).Name;
  95         }
  96
  97         // The following automation peers provide accessiblity support (Raise automation events on receiving keyboard focus)
  98         // This is necessary for ACC-TOOLS especially screen readers like JAWS.
  99         // We cannot use the base AutomationPeers (like UIElementAutomationPeer) and *have* to derive from the respective types
 100         // since the actual implementation of the handler when the focus event differs from element to element.
 101         // So we cannot use single base class to achieve the desired goal.
 102         //
 103
 104
 105         private class InfoTextBlockAutomationPeer : TextBlockAutomationPeer, IAutomationFocusChangedEventSource
 106         {
 107
 108             private TextBlock _informationLabel;
 109
 110             public InfoTextBlockAutomationPeer(TextBlock informationLabel)
 111                 : base(informationLabel)
 112             {
 113                 if (informationLabel == null)
 114                 {
 115                     throw FxTrace.Exception.ArgumentNull("informationLabel");
 116                 }
 117                 _informationLabel = informationLabel;
 118                 _informationLabel.PreviewGotKeyboardFocus += new KeyboardFocusChangedEventHandler(OnPreviewGotKeyboardFocus);
 119             }
 120
 121             // <summary>
 122             // PreviewGotKeyboardFocus event to raise the "AutomationFocus" event.
 123             // </summary>
 124             // <param name="sender">TextBlock</param>
 125             // <param name="e">KeyboardFocusChangedEventArgs</param>
 126             void OnPreviewGotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
 127             {
 128                 this.RaiseAutomationEvent(AutomationEvents.AutomationFocusChanged);
 129             }
 130
 131             protected override AutomationPeer GetLabeledByCore()
 132             {
 133                 return new TextBlockAutomationPeer(_informationLabel);
 134             }
 135
 136         // IAutomationFocusChangedEventSource Members
 137
 138             public void UnloadEventHook()
 139             {
 140                 Owner.PreviewGotKeyboardFocus -= new KeyboardFocusChangedEventHandler(OnPreviewGotKeyboardFocus);
 141             }
 142
 143         }
 144     }
 145 }