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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.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Security;
using System.Text;
using System.Windows;
using System.Windows.Automation.Provider;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Threading;
using MS.Internal;
using MS.Win32;
namespace System.Windows.Automation.Peers
{
///
public class ComboBoxAutomationPeer: SelectorAutomationPeer, IValueProvider, IExpandCollapseProvider
{
///
public ComboBoxAutomationPeer(ComboBox owner): base(owner)
{}
///
override protected ItemAutomationPeer CreateItemAutomationPeer(object item)
{
// Use the same peer as ListBox
return new ListBoxItemAutomationPeer(item, this);
}
///
override protected AutomationControlType GetAutomationControlTypeCore()
{
return AutomationControlType.ComboBox;
}
///
override protected string GetClassNameCore()
{
return "ComboBox";
}
///
override public object GetPattern(PatternInterface pattern)
{
object iface = null;
ComboBox owner = (ComboBox)Owner;
if (pattern == PatternInterface.Value)
{
if (owner.IsEditable) iface = this;
}
else if(pattern == PatternInterface.ExpandCollapse)
{
iface = this;
}
else if (pattern == PatternInterface.Scroll && !owner.IsDropDownOpen)
{
iface = this;
}
else
{
iface = base.GetPattern(pattern);
}
return iface;
}
///
protected override List<AutomationPeer> GetChildrenCore()
{
List<AutomationPeer> children = base.GetChildrenCore();
// include text box part into children collection
ComboBox owner = (ComboBox)Owner;
TextBox textBox = owner.EditableTextBoxSite;
if (textBox != null)
{
AutomationPeer peer = UIElementAutomationPeer.CreatePeerForElement(textBox);
if (peer != null)
{
if (children == null)
children = new List<AutomationPeer>();
children.Insert(0, peer);
}
}
return children;
}
///
protected override void SetFocusCore()
{
ComboBox owner = (ComboBox)Owner;
if (owner.Focusable)
{
if (!owner.Focus())
{
//The fox might have went to the TextBox inside Combobox if it is editable.
if (owner.IsEditable)
{
TextBox tb = owner.EditableTextBoxSite;
if (tb == null || !tb.IsKeyboardFocused)
throw new InvalidOperationException(SR.SetFocusFailed);
}
else
throw new InvalidOperationException(SR.SetFocusFailed);
}
}
else
{
throw new InvalidOperationException(SR.SetFocusFailed);
}
}
///
internal void ScrollItemIntoView(object item)
{
// Item can be scrolled into view only when the Combo is expanded.
// If combo is not expanded the possible solution is expanding scrolling and
// bringing back to original state but that is a breaking change and if there is a strong case can be supported later.
if(((IExpandCollapseProvider)this).ExpandCollapseState == ExpandCollapseState.Expanded)
{
ComboBox owner = (ComboBox)Owner;
if (owner.ItemContainerGenerator.Status == GeneratorStatus.ContainersGenerated)
{
owner.OnBringItemIntoView(item);
}
else
{
// The items aren't generated, try at a later time
Dispatcher.BeginInvoke(DispatcherPriority.Loaded, new DispatcherOperationCallback(owner.OnBringItemIntoView), item);
}
}
}
#region Value
/// <summary>
/// Request to set the value that this UI element is representing
/// </summary>
/// <param name="val">Value to set the UI to, as an object</param>
/// <returns>true if the UI element was successfully set to the specified value</returns>
//[CodeAnalysis("AptcaMethodsShouldOnlyCallAptcaMethods")] //Tracking Bug: 29647
void IValueProvider.SetValue(string val)
{
ArgumentNullException.ThrowIfNull(val);
ComboBox owner = (ComboBox)Owner;
if (!owner.IsEnabled)
throw new ElementNotEnabledException();
owner.SetCurrentValueInternal(ComboBox.TextProperty, val);
}
///<summary>Value of a value control, as a a string.</summary>
string IValueProvider.Value
{
get
{
return ((ComboBox)(((ComboBoxAutomationPeer)this).Owner)).Text;
}
}
///<summary>Indicates that the value can only be read, not modified.
///returns True if the control is read-only</summary>
bool IValueProvider.IsReadOnly
{
get
{
ComboBox owner = (ComboBox)Owner;
return !owner.IsEnabled || owner.IsReadOnly;
}
}
// BUG 1555137: Never inline, as we don't want to unnecessarily link the automation DLL
[System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.NoInlining)]
internal void RaiseValuePropertyChangedEvent(string oldValue, string newValue)
{
if (oldValue != newValue)
{
RaisePropertyChangedEvent(ValuePatternIdentifiers.ValueProperty, oldValue, newValue);
}
}
#endregion Value
#region ExpandCollapse
/// <summary>
/// Blocking method that returns after the element has been expanded.
/// </summary>
/// <returns>true if the node was successfully expanded</returns>
void IExpandCollapseProvider.Expand()
{
if(!IsEnabled())
throw new ElementNotEnabledException();
ComboBox owner = (ComboBox)((ComboBoxAutomationPeer)this).Owner;
owner.SetCurrentValueInternal(ComboBox.IsDropDownOpenProperty, MS.Internal.KnownBoxes.BooleanBoxes.TrueBox);
}
/// <summary>
/// Blocking method that returns after the element has been collapsed.
/// </summary>
/// <returns>true if the node was successfully collapsed</returns>
void IExpandCollapseProvider.Collapse()
{
if(!IsEnabled())
throw new ElementNotEnabledException();
ComboBox owner = (ComboBox)((ComboBoxAutomationPeer)this).Owner;
owner.SetCurrentValueInternal(ComboBox.IsDropDownOpenProperty, MS.Internal.KnownBoxes.BooleanBoxes.FalseBox);
}
///<summary>indicates an element's current Collapsed or Expanded state</summary>
ExpandCollapseState IExpandCollapseProvider.ExpandCollapseState
{
get
{
ComboBox owner = (ComboBox)((ComboBoxAutomationPeer)this).Owner;
return owner.IsDropDownOpen ? ExpandCollapseState.Expanded : ExpandCollapseState.Collapsed;
}
}
// BUG 1555137: Never inline, as we don't want to unnecessarily link the automation DLL
[System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.NoInlining)]
internal void RaiseExpandCollapseAutomationEvent(bool oldValue, bool newValue)
{
RaisePropertyChangedEvent(
ExpandCollapsePatternIdentifiers.ExpandCollapseStateProperty,
oldValue ? ExpandCollapseState.Expanded : ExpandCollapseState.Collapsed,
newValue ? ExpandCollapseState.Expanded : ExpandCollapseState.Collapsed);
}
#endregion ExpandCollapse
}
}
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