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/***************************************************************************\
*
* File: TriggerCollection.cs
*
* A collection of TriggerBase-derived classes. See use in Style.cs and other
* places.
*
* Copyright (C) by Microsoft Corporation. All rights reserved.
*
\***************************************************************************/
using System.Diagnostics;
using System.Collections.Generic;
using System.Collections.ObjectModel; // Collection<T>
using MS.Internal;
namespace System.Windows
{
/// <summary>
/// A set of TriggerBase's
/// </summary>
[Localizability(LocalizationCategory.None, Readability=Readability.Unreadable)]
public sealed class TriggerCollection : Collection<TriggerBase>
{
#region Constructors
internal TriggerCollection() : this(null)
{
}
internal TriggerCollection(FrameworkElement owner) : base()
{
_sealed = false;
_owner = owner;
}
#endregion Constructors
#region ProtectedMethods
/// <summary>
/// ClearItems override
/// </summary>
protected override void ClearItems()
{
CheckSealed();
OnClear();
base.ClearItems();
}
/// <summary>
/// InsertItem override
/// </summary>
protected override void InsertItem(int index, TriggerBase item)
{
CheckSealed();
TriggerBaseValidation(item);
OnAdd(item);
base.InsertItem(index, item);
}
/// <summary>
/// RemoveItem override
/// </summary>
protected override void RemoveItem(int index)
{
CheckSealed();
TriggerBase triggerBase = this[index];
OnRemove(triggerBase);
base.RemoveItem(index);
}
/// <summary>
/// SetItem override
/// </summary>
protected override void SetItem(int index, TriggerBase item)
{
CheckSealed();
TriggerBaseValidation(item);
OnAdd(item);
base.SetItem(index, item);
}
#endregion ProtectedMethods
#region PublicMethods
/// <summary>
/// Returns the sealed state of this object. If true, any attempt
/// at modifying the state of this object will trigger an exception.
/// </summary>
public bool IsSealed
{
get
{
return _sealed;
}
}
#endregion PublicMethods
#region InternalMethods
internal void Seal()
{
Debug.Assert (Owner == null);
_sealed = true;
// Seal all the setters
for (int i=0; i<Count; i++)
{
this[i].Seal();
}
}
// This may be null (i.e. when used in a style or template)
internal FrameworkElement Owner
{
get { return _owner; }
}
#endregion InternalMethods
#region PrivateMethods
private void CheckSealed()
{
if (_sealed)
{
throw new InvalidOperationException(SR.Get(SRID.CannotChangeAfterSealed, "TriggerCollection"));
}
}
private void TriggerBaseValidation(TriggerBase triggerBase)
{
if (triggerBase == null)
{
throw new ArgumentNullException("triggerBase");
}
}
// Called by GenericCollection.tb when a trigger is added to the collection.
// We use this opportunity to hook it into the tree.
private void OnAdd( TriggerBase triggerBase )
{
// If we don't have an Owner (the Style/Template case), or the
// element isn't initialized yet, we don't need to do anything
if (Owner != null && Owner.IsInitialized)
{
EventTrigger.ProcessOneTrigger(Owner, triggerBase);
}
InheritanceContextHelper.ProvideContextForObject(Owner, triggerBase);
}
// Called by GenericCollection.tb when a trigger is removed from the collection.
// We use this opportunity to pull its hooks out of the tree.
private void OnRemove( TriggerBase triggerBase )
{
// If we don't have an Owner (the Style/Template case),
// we don't need to do anything
if (Owner != null)
{
// If the owner is initialized, we need to disconnect the trigger.
if (Owner.IsInitialized)
{
EventTrigger.DisconnectOneTrigger(Owner, triggerBase);
}
// We always need to update the inheritance context
InheritanceContextHelper.RemoveContextFromObject(Owner, triggerBase);
}
}
// Called by GenericCollection.tb when the collection is cleared.
// We use this opportunity to pull all the hooks out of the tree.
private void OnClear()
{
// If we don't have an Owner (the Style/Template case),
// we don't need to do anything
if (Owner != null)
{
// If the owner is initialized, we need to disconnect all the trigger.
if (Owner.IsInitialized)
{
EventTrigger.DisconnectAllTriggers(Owner);
}
// We always need to update the inheritance context
for (int i = Count - 1; i >= 0; i--)
{
InheritanceContextHelper.RemoveContextFromObject(Owner, this[i]);
}
}
}
#endregion PrivateMethods
#region Data
private bool _sealed;
private FrameworkElement _owner;
#endregion Data
}
}
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