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//---------------------------------------------------------------------------
//
// <copyright file="NotifyCollectionChangedEventArgs.cs" company="Microsoft">
// Copyright (C) Microsoft Corporation. All rights reserved.
// </copyright>
//
// Description: NotifyCollectionChanged event arguments
//
// Specs: http://avalon/connecteddata/Specs/INotifyCollectionChanged.mht
//
//---------------------------------------------------------------------------
using System;
using System.Collections;
using System.Diagnostics.Contracts;
using System.Runtime.CompilerServices;
namespace System.Collections.Specialized
{
/// <summary>
/// This enum describes the action that caused a CollectionChanged event.
/// </summary>
[TypeForwardedFrom("WindowsBase, Version=3.0.0.0, Culture=Neutral, PublicKeyToken=31bf3856ad364e35")]
public enum NotifyCollectionChangedAction
{
/// <summary> One or more items were added to the collection. </summary>
Add,
/// <summary> One or more items were removed from the collection. </summary>
Remove,
/// <summary> One or more items were replaced in the collection. </summary>
Replace,
/// <summary> One or more items were moved within the collection. </summary>
Move,
/// <summary> The contents of the collection changed dramatically. </summary>
Reset,
}
/// <summary>
/// Arguments for the CollectionChanged event.
/// A collection that supports INotifyCollectionChangedThis raises this event
/// whenever an item is added or removed, or when the contents of the collection
/// changes dramatically.
/// </summary>
[TypeForwardedFrom("WindowsBase, Version=3.0.0.0, Culture=Neutral, PublicKeyToken=31bf3856ad364e35")]
public class NotifyCollectionChangedEventArgs : EventArgs
{
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs that describes a reset change.
/// </summary>
/// <param name="action">The action that caused the event (must be Reset).</param>
public NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action)
{
if (action != NotifyCollectionChangedAction.Reset)
throw new ArgumentException(SR.GetString(SR.WrongActionForCtor, NotifyCollectionChangedAction.Reset), "action");
InitializeAdd(action, null, -1);
}
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs that describes a one-item change.
/// </summary>
/// <param name="action">The action that caused the event; can only be Reset, Add or Remove action.</param>
/// <param name="changedItem">The item affected by the change.</param>
public NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action, object changedItem)
{
if ((action != NotifyCollectionChangedAction.Add) && (action != NotifyCollectionChangedAction.Remove)
&& (action != NotifyCollectionChangedAction.Reset))
throw new ArgumentException(SR.GetString(SR.MustBeResetAddOrRemoveActionForCtor), "action");
if (action == NotifyCollectionChangedAction.Reset)
{
if (changedItem != null)
throw new ArgumentException(SR.GetString(SR.ResetActionRequiresNullItem), "action");
InitializeAdd(action, null, -1);
}
else
{
InitializeAddOrRemove(action, new object[]{changedItem}, -1);
}
}
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs that describes a one-item change.
/// </summary>
/// <param name="action">The action that caused the event.</param>
/// <param name="changedItem">The item affected by the change.</param>
/// <param name="index">The index where the change occurred.</param>
public NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action, object changedItem, int index)
{
if ((action != NotifyCollectionChangedAction.Add) && (action != NotifyCollectionChangedAction.Remove)
&& (action != NotifyCollectionChangedAction.Reset))
throw new ArgumentException(SR.GetString(SR.MustBeResetAddOrRemoveActionForCtor), "action");
if (action == NotifyCollectionChangedAction.Reset)
{
if (changedItem != null)
throw new ArgumentException(SR.GetString(SR.ResetActionRequiresNullItem), "action");
if (index != -1)
throw new ArgumentException(SR.GetString(SR.ResetActionRequiresIndexMinus1), "action");
InitializeAdd(action, null, -1);
}
else
{
InitializeAddOrRemove(action, new object[]{changedItem}, index);
}
}
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs that describes a multi-item change.
/// </summary>
/// <param name="action">The action that caused the event.</param>
/// <param name="changedItems">The items affected by the change.</param>
public NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action, IList changedItems)
{
if ((action != NotifyCollectionChangedAction.Add) && (action != NotifyCollectionChangedAction.Remove)
&& (action != NotifyCollectionChangedAction.Reset))
throw new ArgumentException(SR.GetString(SR.MustBeResetAddOrRemoveActionForCtor), "action");
if (action == NotifyCollectionChangedAction.Reset)
{
if (changedItems != null)
throw new ArgumentException(SR.GetString(SR.ResetActionRequiresNullItem), "action");
InitializeAdd(action, null, -1);
}
else
{
if (changedItems == null)
throw new ArgumentNullException("changedItems");
InitializeAddOrRemove(action, changedItems, -1);
}
}
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs that describes a multi-item change (or a reset).
/// </summary>
/// <param name="action">The action that caused the event.</param>
/// <param name="changedItems">The items affected by the change.</param>
/// <param name="startingIndex">The index where the change occurred.</param>
public NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action, IList changedItems, int startingIndex)
{
if ((action != NotifyCollectionChangedAction.Add) && (action != NotifyCollectionChangedAction.Remove)
&& (action != NotifyCollectionChangedAction.Reset))
throw new ArgumentException(SR.GetString(SR.MustBeResetAddOrRemoveActionForCtor), "action");
if (action == NotifyCollectionChangedAction.Reset)
{
if (changedItems != null)
throw new ArgumentException(SR.GetString(SR.ResetActionRequiresNullItem), "action");
if (startingIndex != -1)
throw new ArgumentException(SR.GetString(SR.ResetActionRequiresIndexMinus1), "action");
InitializeAdd(action, null, -1);
}
else
{
if (changedItems == null)
throw new ArgumentNullException("changedItems");
if (startingIndex < -1)
throw new ArgumentException(SR.GetString(SR.IndexCannotBeNegative), "startingIndex");
InitializeAddOrRemove(action, changedItems, startingIndex);
}
}
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs that describes a one-item Replace event.
/// </summary>
/// <param name="action">Can only be a Replace action.</param>
/// <param name="newItem">The new item replacing the original item.</param>
/// <param name="oldItem">The original item that is replaced.</param>
public NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action, object newItem, object oldItem)
{
if (action != NotifyCollectionChangedAction.Replace)
throw new ArgumentException(SR.GetString(SR.WrongActionForCtor, NotifyCollectionChangedAction.Replace), "action");
InitializeMoveOrReplace(action, new object[]{newItem}, new object[]{oldItem}, -1, -1);
}
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs that describes a one-item Replace event.
/// </summary>
/// <param name="action">Can only be a Replace action.</param>
/// <param name="newItem">The new item replacing the original item.</param>
/// <param name="oldItem">The original item that is replaced.</param>
/// <param name="index">The index of the item being replaced.</param>
public NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action, object newItem, object oldItem, int index)
{
if (action != NotifyCollectionChangedAction.Replace)
throw new ArgumentException(SR.GetString(SR.WrongActionForCtor, NotifyCollectionChangedAction.Replace), "action");
int oldStartingIndex = index;
#if FEATURE_LEGACYNETCF
if (CompatibilitySwitches.IsAppEarlierThanWindowsPhone8)
{
// Dev11 444113 quirk:
// This is a "Replace" so the old and new index should both be set to the index passed in however
// NetCF on Mango incorrectly leaves OldStartingIndex at -1 and Mango apps depend on this behavior.
oldStartingIndex = -1;
}
#endif
InitializeMoveOrReplace(action, new object[]{newItem}, new object[]{oldItem}, index, oldStartingIndex);
}
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs that describes a multi-item Replace event.
/// </summary>
/// <param name="action">Can only be a Replace action.</param>
/// <param name="newItems">The new items replacing the original items.</param>
/// <param name="oldItems">The original items that are replaced.</param>
public NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action, IList newItems, IList oldItems)
{
if (action != NotifyCollectionChangedAction.Replace)
throw new ArgumentException(SR.GetString(SR.WrongActionForCtor, NotifyCollectionChangedAction.Replace), "action");
if (newItems == null)
throw new ArgumentNullException("newItems");
if (oldItems == null)
throw new ArgumentNullException("oldItems");
InitializeMoveOrReplace(action, newItems, oldItems, -1, -1);
}
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs that describes a multi-item Replace event.
/// </summary>
/// <param name="action">Can only be a Replace action.</param>
/// <param name="newItems">The new items replacing the original items.</param>
/// <param name="oldItems">The original items that are replaced.</param>
/// <param name="startingIndex">The starting index of the items being replaced.</param>
public NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action, IList newItems, IList oldItems, int startingIndex)
{
if (action != NotifyCollectionChangedAction.Replace)
throw new ArgumentException(SR.GetString(SR.WrongActionForCtor, NotifyCollectionChangedAction.Replace), "action");
if (newItems == null)
throw new ArgumentNullException("newItems");
if (oldItems == null)
throw new ArgumentNullException("oldItems");
InitializeMoveOrReplace(action, newItems, oldItems, startingIndex, startingIndex);
}
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs that describes a one-item Move event.
/// </summary>
/// <param name="action">Can only be a Move action.</param>
/// <param name="changedItem">The item affected by the change.</param>
/// <param name="index">The new index for the changed item.</param>
/// <param name="oldIndex">The old index for the changed item.</param>
public NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action, object changedItem, int index, int oldIndex)
{
if (action != NotifyCollectionChangedAction.Move)
throw new ArgumentException(SR.GetString(SR.WrongActionForCtor, NotifyCollectionChangedAction.Move), "action");
if (index < 0)
throw new ArgumentException(SR.GetString(SR.IndexCannotBeNegative), "index");
object[] changedItems= new object[] {changedItem};
InitializeMoveOrReplace(action, changedItems, changedItems, index, oldIndex);
}
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs that describes a multi-item Move event.
/// </summary>
/// <param name="action">The action that caused the event.</param>
/// <param name="changedItems">The items affected by the change.</param>
/// <param name="index">The new index for the changed items.</param>
/// <param name="oldIndex">The old index for the changed items.</param>
public NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action, IList changedItems, int index, int oldIndex)
{
if (action != NotifyCollectionChangedAction.Move)
throw new ArgumentException(SR.GetString(SR.WrongActionForCtor, NotifyCollectionChangedAction.Move), "action");
if (index < 0)
throw new ArgumentException(SR.GetString(SR.IndexCannotBeNegative), "index");
InitializeMoveOrReplace(action, changedItems, changedItems, index, oldIndex);
}
/// <summary>
/// Construct a NotifyCollectionChangedEventArgs with given fields (no validation). Used by WinRT marshaling.
/// </summary>
internal NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction action, IList newItems, IList oldItems, int newIndex, int oldIndex)
{
_action = action;
#if FEATURE_LEGACYNETCF
if (CompatibilitySwitches.IsAppEarlierThanWindowsPhone8)
{
_newItems = newItems;
}
else
#endif
{
_newItems = (newItems == null) ? null : ArrayList.ReadOnly(newItems);
}
_oldItems = (oldItems == null) ? null : ArrayList.ReadOnly(oldItems);
_newStartingIndex = newIndex;
_oldStartingIndex = oldIndex;
}
private void InitializeAddOrRemove(NotifyCollectionChangedAction action, IList changedItems, int startingIndex)
{
if (action == NotifyCollectionChangedAction.Add)
InitializeAdd(action, changedItems, startingIndex);
else if (action == NotifyCollectionChangedAction.Remove)
InitializeRemove(action, changedItems, startingIndex);
else
Contract.Assert(false, String.Format("Unsupported action: {0}", action.ToString()));
}
private void InitializeAdd(NotifyCollectionChangedAction action, IList newItems, int newStartingIndex)
{
_action = action;
#if FEATURE_LEGACYNETCF
if (CompatibilitySwitches.IsAppEarlierThanWindowsPhone8)
{
_newItems = newItems;
}
else
#endif // !FEATURE_LEGACYNETCF
{
_newItems = (newItems == null) ? null : ArrayList.ReadOnly(newItems);
}
_newStartingIndex = newStartingIndex;
}
private void InitializeRemove(NotifyCollectionChangedAction action, IList oldItems, int oldStartingIndex)
{
_action = action;
_oldItems = (oldItems == null) ? null : ArrayList.ReadOnly(oldItems);
_oldStartingIndex= oldStartingIndex;
}
private void InitializeMoveOrReplace(NotifyCollectionChangedAction action, IList newItems, IList oldItems, int startingIndex, int oldStartingIndex)
{
InitializeAdd(action, newItems, startingIndex);
InitializeRemove(action, oldItems, oldStartingIndex);
}
//------------------------------------------------------
//
// Public Properties
//
//------------------------------------------------------
/// <summary>
/// The action that caused the event.
/// </summary>
public NotifyCollectionChangedAction Action
{
get { return _action; }
}
/// <summary>
/// The items affected by the change.
/// </summary>
public IList NewItems
{
get { return _newItems; }
}
/// <summary>
/// The old items affected by the change (for Replace events).
/// </summary>
public IList OldItems
{
get { return _oldItems; }
}
/// <summary>
/// The index where the change occurred.
/// </summary>
public int NewStartingIndex
{
get { return _newStartingIndex; }
}
/// <summary>
/// The old index where the change occurred (for Move events).
/// </summary>
public int OldStartingIndex
{
get { return _oldStartingIndex; }
}
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
private NotifyCollectionChangedAction _action;
private IList _newItems, _oldItems;
private int _newStartingIndex = -1;
private int _oldStartingIndex = -1;
}
/// <summary>
/// The delegate to use for handlers that receive the CollectionChanged event.
/// </summary>
[TypeForwardedFrom("WindowsBase, Version=3.0.0.0, Culture=Neutral, PublicKeyToken=31bf3856ad364e35")]
public delegate void NotifyCollectionChangedEventHandler(object sender, NotifyCollectionChangedEventArgs e);
}
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