//
// System.Windows.Automation.Peers.AutomationCacheProperty
//
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//
// Copyright (C) 2009 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.Collections.Generic;
using System.Windows.Automation.Provider;
namespace System.Windows.Automation.Peers{
// Internal interface used by AutomationSingleton.InvalidatePeer to raise Automation Events
internal interface IAutomationCacheProperty {
AutomationProperty Property { get; set; }
object OldValue { get; set; }
bool CompareValues (out object oldValue);
}
// Class used by AutomationPeer to cache main properties
internal class AutomationCacheProperty<TResult> : IAutomationCacheProperty {
public AutomationProperty Property {
get; set;
}
public virtual object OldValue {
get; set;
}
public Func<TResult> Delegate {
get; set;
}
public bool CompareValues (out object oldValue)
{
object newValue = Delegate ();
if (object.Equals (newValue, OldValue)) {
oldValue = null;
return false;
} else {
oldValue = OldValue;
OldValue = newValue;
return true;
}
}
}
internal sealed class AutomationCachePeerProperty : AutomationCacheProperty<AutomationPeer> {
public override object OldValue {
get { return reference.Target; }
set {
if (reference == null)
reference = new WeakReference (value);
else
reference.Target = value;
}
}
private WeakReference reference;
}
}
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