Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Core / CSharp / System / Windows / Input / FocusManager.cs / 1305600 / FocusManager.cs
//---------------------------------------------------------------------------- // // Copyright (C) Microsoft Corporation. All rights reserved. // //--------------------------------------------------------------------------- using System; using System.Collections; using System.Collections.Generic; using System.Collections.ObjectModel; using System.ComponentModel; using System.Diagnostics; using System.Windows.Threading; using System.Threading; using System.Windows; using System.Windows.Interop; using System.Windows.Media; using System.Windows.Media.Media3D; using System.Security; using System.Security.Permissions; using MS.Internal.KnownBoxes; namespace System.Windows.Input { ////// FocusManager define attached property used for tracking the FocusedElement with a focus scope /// public static class FocusManager { #region Public Events ////// GotFocus event /// public static readonly RoutedEvent GotFocusEvent = EventManager.RegisterRoutedEvent("GotFocus", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(FocusManager)); ////// LostFocus event /// public static readonly RoutedEvent LostFocusEvent = EventManager.RegisterRoutedEvent("LostFocus", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(FocusManager)); #endregion Public Events #region Public Properties #region FocusedElement property ////// The DependencyProperty for the FocusedElement property. This internal property tracks IsActive /// element ref inside TrackFocus /// Default Value: null /// public static readonly DependencyProperty FocusedElementProperty = DependencyProperty.RegisterAttached( "FocusedElement", typeof(IInputElement), typeof(FocusManager), new PropertyMetadata(new PropertyChangedCallback(OnFocusedElementChanged))); #endregion FocusedElement property #region IsFocusScope Property ////// The DependencyProperty for the IsFocusScope property. /// This property is used to mark the special containers (like Window, Menu) so they can /// keep track of the FocusedElement element inside the container. Once focus is set /// on the container - it is delegated to the FocusedElement element /// Default Value: false /// public static readonly DependencyProperty IsFocusScopeProperty = DependencyProperty.RegisterAttached("IsFocusScope", typeof(bool), typeof(FocusManager), new PropertyMetadata(BooleanBoxes.FalseBox)); #endregion IsFocusScope Property #endregion #region Public static methods ////// Return the property value of FocusedElement property. /// /// ///[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] public static IInputElement GetFocusedElement(DependencyObject element) { return GetFocusedElement(element, false); } /// /// Return the property value of FocusedElement property. The return value is validated /// to be in the subtree of element. If FocusedElement element is not a descendant of element this method return null /// /// /// ////// /// Critical: This code accesses PresentationSource.CriticalFromVisual which is critical /// TreatAsSafe: This code does not expose it and simply uses it for determining if the FocusedElement is valid /// [SecurityCritical, SecurityTreatAsSafe] internal static IInputElement GetFocusedElement(DependencyObject element, bool validate) { if (element == null) { throw new ArgumentNullException("element"); } DependencyObject focusedElement = (DependencyObject) element.GetValue(FocusedElementProperty); // Validate FocusedElement wrt to its FocusScope. If the two do not belong to the same PresentationSource // then sever this link between them. The classic scenario for this is when an element with logical focus is // dragged out into a floating widow. We want to prevent the MainWindow (focus scope) to point to the // element in the floating window as its logical FocusedElement. if (validate && focusedElement != null) { DependencyObject focusScope = element; if (PresentationSource.CriticalFromVisual(focusScope) != PresentationSource.CriticalFromVisual(focusedElement)) { SetFocusedElement(focusScope, null); focusedElement = null; } } return (IInputElement)focusedElement; } ////// Set FocusedElement property for element. /// /// /// public static void SetFocusedElement(DependencyObject element, IInputElement value) { if (element == null) { throw new ArgumentNullException("element"); } element.SetValue(FocusedElementProperty, value); } ////// Writes the attached property IsFocusScope to the given element. /// /// The element to which to write the attached property. /// The property value to set public static void SetIsFocusScope(DependencyObject element, bool value) { if (element == null) { throw new ArgumentNullException("element"); } element.SetValue(IsFocusScopeProperty, value); } ////// Reads the attached property IsFocusScope from the given element. /// /// The element from which to read the attached property. ///The property's value. public static bool GetIsFocusScope(DependencyObject element) { if (element == null) { throw new ArgumentNullException("element"); } return (bool)element.GetValue(IsFocusScopeProperty); } ////// Find the closest visual ancestor that has IsFocusScope set to true /// /// ///public static DependencyObject GetFocusScope(DependencyObject element) { if (element == null) { throw new ArgumentNullException("element"); } return _GetFocusScope(element); } #endregion Public methods #region private implementation // private static void OnFocusedElementChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { IInputElement newFocusedElement = (IInputElement)e.NewValue; DependencyObject oldVisual = (DependencyObject)e.OldValue; DependencyObject newVisual = (DependencyObject)e.NewValue; if (oldVisual != null) { oldVisual.ClearValue(UIElement.IsFocusedPropertyKey); } if (newVisual != null) { // set IsFocused on the element. The element may redirect Keyboard focus // in response to this (e.g. Editable ComboBox redirects to the // child TextBox), so detect whether this happens. DependencyObject oldFocus = Keyboard.FocusedElement as DependencyObject; newVisual.SetValue(UIElement.IsFocusedPropertyKey, BooleanBoxes.TrueBox); DependencyObject newFocus = Keyboard.FocusedElement as DependencyObject; // set the Keyboard focus to the new element, provided that // a) the element didn't already set Keyboard focus // b) Keyboard focus is not already on the new element // c) the new element is within the same focus scope as the current // holder (if any) of Keyboard focus if (oldFocus == newFocus && newVisual != newFocus && (newFocus == null || GetRoot(newVisual) == GetRoot(newFocus))) { Keyboard.Focus(newFocusedElement); } } /* if (!_currentlyUpdatingTree) { _currentlyUpdatingTree = true; IInputElement newFocusedElement = (IInputElement) newValue; Visual oldVisual = GetNearestVisual(args.OldValue); Visual newVisual = GetNearestVisual(args.NewValue); if (oldVisual != null) { oldVisual.ClearValue(UIElement.IsFocusedPropertyKey); // reverse-inherit: clear the property on all parents that aren't also in the // new focused element ancestry while (oldVisual != null) { oldVisual.ClearValue(FocusedElementProperty); oldVisual = VisualTreeHelper.GetParent(oldVisual); if ((oldVisual == newVisual) || oldVisual.IsAncestorOf(newVisual)) { // only walk up until you reach a common parent -- the new value walk will take care of the rest break; } } } if (newVisual != null) { newVisual.SetValue(UIElement.IsFocusedPropertyKey, BooleanBoxes.TrueBox); // reverse-inherit: set the property on all parents while (newVisual != null) { newVisual.SetValue(FocusedElementProperty, newFocusedElement); newVisual = VisualTreeHelper.GetParent(newVisual); } // Set Keyboard focus to the element if not already focused && current focus is within the current focus scope DependencyObject currentFocus = Keyboard.FocusedElement as DependencyObject; if ((currentFocus == null) && (newVisual != currentFocus) && (GetRoot(newVisual) == GetRoot(currentFocus))) { Keyboard.Focus(newFocusedElement); } } _currentlyUpdatingTree = false; } */ } /* private static Visual GetNearestVisual(object value) { Visual visual = null; if (value != null) { visual = value as Visual; if (visual == null) { ContentElement ce = value as ContentElement; if (ce != null) { visual = ce.GetUIParent() as Visual; } } } return visual; } */ private static DependencyObject GetRoot(DependencyObject element) { if (element == null) return null; DependencyObject parent = null; DependencyObject dependencyObject = element; ContentElement ce = element as ContentElement; if (ce != null) dependencyObject = ce.GetUIParent(); while (dependencyObject != null) { parent = dependencyObject; dependencyObject = VisualTreeHelper.GetParent(dependencyObject); } return parent; } // Walk up the parent chain to find the closest element with IsFocusScope=true private static DependencyObject _GetFocusScope(DependencyObject d) { if (d == null) return null; if ((bool)d.GetValue(IsFocusScopeProperty)) return d; // Step 1: Walk up the logical tree UIElement uiElement = d as UIElement; if (uiElement != null) { DependencyObject logicalParent = uiElement.GetUIParentCore(); if (logicalParent != null) { return GetFocusScope(logicalParent); } } else { ContentElement ce = d as ContentElement; if (ce != null) { DependencyObject logicalParent = ce.GetUIParent(true); if (logicalParent != null) { return _GetFocusScope(logicalParent); } } else { UIElement3D uiElement3D = d as UIElement3D; if (uiElement3D != null) { DependencyObject logicalParent = uiElement3D.GetUIParentCore(); if (logicalParent != null) { return GetFocusScope(logicalParent); } } } } // Step 2: Walk up the visual tree if (d is Visual || d is Visual3D) { DependencyObject visualParent = VisualTreeHelper.GetParent(d); if (visualParent != null) { return _GetFocusScope(visualParent); } } // If visual and logical parent is null - then the element is implicit focus scope return d; } #endregion private implementation #region private data private static readonly UncommonField IsFocusedElementSet = new UncommonField (); private static readonly UncommonField FocusedElementWeakCacheField = new UncommonField (); private static readonly UncommonField IsFocusedElementCacheValid = new UncommonField (); private static readonly UncommonField FocusedElementCache = new UncommonField (); // private static bool _currentlyUpdatingTree = false; #endregion private data } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. 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