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//---------------------------------------------------------------------------
//
// <copyright file="LostFocusEventManager.cs" company="Microsoft">
// Copyright (C) Microsoft Corporation. All rights reserved.
// </copyright>
//
// Description: Manager for the LostFocus event in the "weak event listener"
// pattern. See WeakEventTable.cs for an overview.
//
//---------------------------------------------------------------------------
using System;
using System.Windows; // WeakEventManager
using MS.Internal; // Helper
namespace System.Windows
{
/// <summary>
/// Manager for the DependencyObject.LostFocus event.
/// </summary>
public class LostFocusEventManager : WeakEventManager
{
#region Constructors
//
// Constructors
//
private LostFocusEventManager()
{
}
#endregion Constructors
#region Public Methods
//
// Public Methods
//
/// <summary>
/// Add a listener to the given source's event.
/// </summary>
public static void AddListener(DependencyObject source, IWeakEventListener listener)
{
if (source == null)
throw new ArgumentNullException("source");
if (listener == null)
throw new ArgumentNullException("listener");
CurrentManager.ProtectedAddListener(source, listener);
}
/// <summary>
/// Remove a listener to the given source's event.
/// </summary>
public static void RemoveListener(DependencyObject source, IWeakEventListener listener)
{
if (source == null)
throw new ArgumentNullException("source");
if (listener == null)
throw new ArgumentNullException("listener");
CurrentManager.ProtectedRemoveListener(source, listener);
}
/// <summary>
/// Add a handler for the given source's event.
/// </summary>
public static void AddHandler(DependencyObject source, EventHandler<RoutedEventArgs> handler)
{
if (handler == null)
throw new ArgumentNullException("handler");
CurrentManager.ProtectedAddHandler(source, handler);
}
/// <summary>
/// Remove a handler for the given source's event.
/// </summary>
public static void RemoveHandler(DependencyObject source, EventHandler<RoutedEventArgs> handler)
{
if (handler == null)
throw new ArgumentNullException("handler");
CurrentManager.ProtectedRemoveHandler(source, handler);
}
#endregion Public Methods
#region Protected Methods
//
// Protected Methods
//
/// <summary>
/// Return a new list to hold listeners to the event.
/// </summary>
protected override ListenerList NewListenerList()
{
return new ListenerList<RoutedEventArgs>();
}
/// <summary>
/// Listen to the given source for the event.
/// </summary>
protected override void StartListening(object source)
{
DependencyObject typedSource = (DependencyObject)source;
FrameworkElement fe;
FrameworkContentElement fce;
Helper.DowncastToFEorFCE(typedSource, out fe, out fce, true);
if (fe != null)
fe.LostFocus += new RoutedEventHandler(OnLostFocus);
else if (fce != null)
fce.LostFocus += new RoutedEventHandler(OnLostFocus);
}
/// <summary>
/// Stop listening to the given source for the event.
/// </summary>
protected override void StopListening(object source)
{
DependencyObject typedSource = (DependencyObject)source;
FrameworkElement fe;
FrameworkContentElement fce;
Helper.DowncastToFEorFCE(typedSource, out fe, out fce, true);
if (fe != null)
fe.LostFocus -= new RoutedEventHandler(OnLostFocus);
else if (fce != null)
fce.LostFocus -= new RoutedEventHandler(OnLostFocus);
}
#endregion Protected Methods
#region Private Properties
//
// Private Properties
//
// get the event manager for the current thread
private static LostFocusEventManager CurrentManager
{
get
{
Type managerType = typeof(LostFocusEventManager);
LostFocusEventManager manager = (LostFocusEventManager)GetCurrentManager(managerType);
// at first use, create and register a new manager
if (manager == null)
{
manager = new LostFocusEventManager();
SetCurrentManager(managerType, manager);
}
return manager;
}
}
#endregion Private Properties
#region Private Methods
//
// Private Methods
//
// event handler for LostFocus event
private void OnLostFocus(object sender, RoutedEventArgs args)
{
DeliverEvent(sender, args);
}
#endregion Private Methods
}
}
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