Steven Kirk
11 years ago
11 changed files with 493 additions and 326 deletions
@ -1,21 +0,0 @@ |
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// -----------------------------------------------------------------------
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// <copyright file="IKeyboardNavigation.cs" company="Steven Kirk">
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// Copyright 2014 MIT Licence. See licence.md for more information.
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// </copyright>
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// -----------------------------------------------------------------------
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namespace Perspex.Input |
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{ |
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public interface IKeyboardNavigation |
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{ |
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IInputElement GetNextInTabOrder(IInputElement element); |
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IInputElement GetPreviousInTabOrder(IInputElement element); |
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void TabNext(IInputElement element); |
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void TabPrevious(IInputElement element); |
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void TabTo(IInputElement element); |
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} |
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} |
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@ -0,0 +1,35 @@ |
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// -----------------------------------------------------------------------
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// <copyright file="IKeyboardNavigationHandler.cs" company="Steven Kirk">
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// Copyright 2015 MIT Licence. See licence.md for more information.
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// </copyright>
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// -----------------------------------------------------------------------
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namespace Perspex.Input |
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{ |
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/// <summary>
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/// Defines the interface for classes that handle keyboard navigation for a window.
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/// </summary>
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public interface IKeyboardNavigationHandler |
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{ |
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/// <summary>
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/// Sets the owner of the keyboard navigation handler.
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/// </summary>
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/// <param name="owner">The owner.</param>
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/// <remarks>
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/// This method can only be called once, typically by the owner itself on creation.
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/// </remarks>
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void SetOwner(IInputRoot owner); |
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/// <summary>
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/// Moves the focus to the next control in tab order.
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/// </summary>
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/// <param name="element">The current element.</param>
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void TabNext(IInputElement element); |
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/// <summary>
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/// Moves the focus to the previous control in tab order.
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/// </summary>
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/// <param name="element">The current element.</param>
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void TabPrevious(IInputElement element); |
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} |
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} |
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@ -0,0 +1,362 @@ |
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// -----------------------------------------------------------------------
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// <copyright file="KeyboardNavigationHandler.cs" company="Steven Kirk">
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// Copyright 2015 MIT Licence. See licence.md for more information.
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// </copyright>
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// -----------------------------------------------------------------------
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namespace Perspex.Input |
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{ |
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using System; |
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using System.Collections.Generic; |
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using System.Linq; |
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using Perspex.VisualTree; |
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/// <summary>
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/// Handles keyboard navigation for a window.
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/// </summary>
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public class KeyboardNavigationHandler : IKeyboardNavigationHandler |
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{ |
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/// <summary>
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/// The window to which the handler belongs.
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/// </summary>
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private IInputRoot owner; |
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/// <summary>
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/// Sets the owner of the keyboard navigation handler.
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/// </summary>
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/// <param name="owner">The owner.</param>
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/// <remarks>
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/// This method can only be called once, typically by the owner itself on creation.
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/// </remarks>
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public void SetOwner(IInputRoot owner) |
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{ |
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Contract.Requires<ArgumentNullException>(owner != null); |
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if (this.owner != null) |
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{ |
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throw new InvalidOperationException("AccessKeyHandler owner has already been set."); |
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} |
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this.owner = owner; |
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this.owner.AddHandler(InputElement.KeyDownEvent, this.OnKeyDown); |
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} |
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/// <summary>
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/// Gets the next element in tab order.
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/// </summary>
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/// <param name="element">The element.</param>
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/// <returns>The next element in tab order.</returns>
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public static IInputElement GetNextInTabOrder(IInputElement element) |
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{ |
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Contract.Requires<ArgumentNullException>(element != null); |
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var container = element.GetVisualParent<IInputElement>(); |
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if (container != null) |
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{ |
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var mode = KeyboardNavigation.GetTabNavigation((InputElement)container); |
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switch (mode) |
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{ |
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case KeyboardNavigationMode.Continue: |
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return GetNextInContainer(element, container) ?? |
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GetFirstInNextContainer(container); |
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case KeyboardNavigationMode.Cycle: |
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return GetNextInContainer(element, container) ?? |
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GetDescendents(container).FirstOrDefault(); |
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default: |
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return GetFirstInNextContainer(container); |
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} |
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} |
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else |
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{ |
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return GetDescendents(element).FirstOrDefault(); |
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} |
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} |
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/// <summary>
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/// Gets the next element in tab order.
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/// </summary>
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/// <param name="element">The element.</param>
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/// <returns>The next element in tab order.</returns>
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public static IInputElement GetPreviousInTabOrder(IInputElement element) |
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{ |
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Contract.Requires<ArgumentNullException>(element != null); |
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var container = element.GetVisualParent<IInputElement>(); |
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if (container != null) |
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{ |
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var mode = KeyboardNavigation.GetTabNavigation((InputElement)container); |
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switch (mode) |
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{ |
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case KeyboardNavigationMode.Continue: |
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return GetPreviousInContainer(element, container) ?? |
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GetLastInPreviousContainer(element); |
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case KeyboardNavigationMode.Cycle: |
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return GetPreviousInContainer(element, container) ?? |
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GetDescendents(container).LastOrDefault(); |
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default: |
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return GetLastInPreviousContainer(container); |
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} |
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} |
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else |
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{ |
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return GetDescendents(element).LastOrDefault(); |
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} |
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} |
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/// <summary>
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/// Moves the focus to the next control in tab order.
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/// </summary>
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/// <param name="element">The current element.</param>
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public void TabNext(IInputElement element) |
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{ |
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Contract.Requires<ArgumentNullException>(element != null); |
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var next = GetNextInTabOrder(element); |
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if (next != null) |
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{ |
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FocusManager.Instance.Focus(next, true); |
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} |
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} |
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/// <summary>
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/// Moves the focus to the previous control in tab order.
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/// </summary>
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/// <param name="element">The current element.</param>
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public void TabPrevious(IInputElement element) |
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{ |
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Contract.Requires<ArgumentNullException>(element != null); |
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var next = GetPreviousInTabOrder(element); |
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if (next != null) |
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{ |
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FocusManager.Instance.Focus(next, true); |
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} |
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} |
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/// <summary>
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/// Checks if the specified element can be focused.
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/// </summary>
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/// <param name="e">The element.</param>
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/// <returns>True if the element can be focused.</returns>
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private static bool CanFocus(IInputElement e) => e.Focusable && e.IsEnabledCore && e.IsVisible; |
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/// <summary>
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/// Checks if a descendent of the specified element can be focused.
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/// </summary>
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/// <param name="e">The element.</param>
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/// <returns>True if a descendent of the element can be focused.</returns>
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private static bool CanFocusDescendent(IInputElement e) => e.IsEnabledCore && e.IsVisible; |
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/// <summary>
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/// Gets the focusable descendents of the specified element, depending on the element's
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/// <see cref="KeyboardNavigation.TabNavigationProperty"/>.
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/// </summary>
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/// <param name="element">The element.</param>
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/// <returns>The element's focusable descendents.</returns>
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private static IEnumerable<IInputElement> GetDescendents(IInputElement element) |
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{ |
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var mode = KeyboardNavigation.GetTabNavigation((InputElement)element); |
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if (mode == KeyboardNavigationMode.Never) |
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{ |
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yield break; |
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} |
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var children = element.GetVisualChildren().OfType<IInputElement>(); |
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if (mode == KeyboardNavigationMode.Once) |
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{ |
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var active = KeyboardNavigation.GetTabOnceActiveElement((InputElement)element); |
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if (active != null) |
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{ |
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yield return active; |
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yield break; |
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} |
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else |
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{ |
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children = children.Take(1); |
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} |
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} |
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foreach (var child in children) |
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{ |
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if (CanFocus(child)) |
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{ |
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yield return child; |
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} |
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if (CanFocusDescendent(child)) |
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{ |
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foreach (var descendent in GetDescendents(child)) |
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{ |
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yield return descendent; |
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} |
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} |
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} |
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} |
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/// <summary>
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/// Gets the next item that should be focused in the specified container.
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/// </summary>
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/// <param name="element">The starting element/</param>
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/// <param name="container">The container.</param>
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/// <returns>The next element, or null if the element is the last.</returns>
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private static IInputElement GetNextInContainer(IInputElement element, IInputElement container) |
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{ |
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var descendent = GetDescendents(element).FirstOrDefault(); |
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if (descendent != null) |
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{ |
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return descendent; |
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} |
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else if (container != null) |
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{ |
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var sibling = container.GetVisualChildren() |
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.OfType<IInputElement>() |
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.Where(CanFocus) |
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.SkipWhile(x => x != element) |
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.Skip(1) |
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.FirstOrDefault(); |
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if (sibling != null) |
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{ |
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return sibling; |
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} |
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} |
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return null; |
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} |
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/// <summary>
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/// Gets the previous item that should be focused in the specified container.
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/// </summary>
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/// <param name="element">The starting element/</param>
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/// <param name="container">The container.</param>
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/// <returns>The previous element, or null if the element is the first.</returns>
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private static IInputElement GetPreviousInContainer(IInputElement element, IInputElement container) |
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{ |
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return container.GetVisualChildren() |
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.OfType<IInputElement>() |
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.Where(CanFocus) |
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.TakeWhile(x => x != element) |
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.LastOrDefault(); |
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} |
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/// <summary>
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/// Gets the first item that should be focused in the next container.
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/// </summary>
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/// <param name="container">The container.</param>
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/// <returns>The first element, or null if there are no more elements.</returns>
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private static IInputElement GetFirstInNextContainer(IInputElement container) |
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{ |
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var parent = container.GetVisualParent<IInputElement>(); |
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IInputElement next = null; |
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if (parent != null) |
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{ |
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var sibling = parent.GetVisualChildren() |
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.OfType<IInputElement>() |
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.Where(CanFocusDescendent) |
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.SkipWhile(x => x != container) |
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.Skip(1) |
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.FirstOrDefault(); |
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if (sibling != null) |
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{ |
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if (CanFocus(sibling)) |
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{ |
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next = sibling; |
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} |
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else |
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{ |
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next = GetDescendents(sibling).FirstOrDefault(); |
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} |
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} |
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if (next == null) |
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{ |
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next = GetFirstInNextContainer(parent); |
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} |
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} |
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else |
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{ |
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next = GetDescendents(container).FirstOrDefault(); |
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} |
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return next; |
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} |
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/// <summary>
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/// Gets the last item that should be focused in the previous container.
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/// </summary>
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/// <param name="container">The container.</param>
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/// <returns>The next element, or null if there are no more elements.</returns>
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private static IInputElement GetLastInPreviousContainer(IInputElement container) |
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{ |
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var parent = container.GetVisualParent<IInputElement>(); |
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IInputElement next = null; |
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if (parent != null) |
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{ |
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var sibling = parent.GetVisualChildren() |
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.OfType<IInputElement>() |
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.Where(CanFocusDescendent) |
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.TakeWhile(x => x != container) |
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.LastOrDefault(); |
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if (sibling != null) |
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{ |
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if (CanFocus(sibling)) |
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{ |
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next = sibling; |
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} |
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else |
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{ |
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next = GetDescendents(sibling).LastOrDefault(); |
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} |
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} |
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if (next == null) |
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{ |
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next = GetLastInPreviousContainer(parent); |
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} |
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} |
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else |
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{ |
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next = GetDescendents(container).LastOrDefault(); |
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} |
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return next; |
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} |
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/// <summary>
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/// Handles the Tab key being pressed in the window.
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/// </summary>
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/// <param name="sender">The event sender.</param>
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/// <param name="e">The event args.</param>
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protected virtual void OnKeyDown(object sender, KeyEventArgs e) |
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{ |
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var current = FocusManager.Instance.Current; |
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if (e.Key == Key.Tab && current != null) |
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{ |
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if ((KeyboardDevice.Instance.Modifiers & ModifierKeys.Shift) == 0) |
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{ |
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this.TabNext(current); |
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} |
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else |
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{ |
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this.TabPrevious(current); |
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} |
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} |
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} |
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} |
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} |
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Reference in new issue