/// <summary>
/// Removes the element at the specified index of the <see cref="T:System.Collections.ObjectModel.Collection`1"/>.
/// </summary>
/// <param name="index">The zero-based index of the element to remove.</param>
/// <exception cref="T:System.ArgumentOutOfRangeException">
/// <paramref name="index"/> is less than zero.-or-<paramref name="index"/> is equal to or greater than <see cref="P:System.Collections.ObjectModel.Collection`1.Count"/>.</exception>
protected override void RemoveItem(int index)
{
T item = default(T);
PerformSyncedAction(() =>
{
VerifyIndex(index);
item = this[index];
});
if (!this.SuppressEvents)
{
CancelableListModificationEventArgs <T> eventArgs = new CancelableListModificationEventArgs <T>(item);
this.ElementRemoving.RaiseEvent(this, eventArgs);
if (eventArgs.Cancel)
{
return;
}
}
// create a command which simply removes the item at the given index and as undo function it re-inserts the item at the index specified.
// The command created passes the current item at the index specified, but it's not really used, as there's no state to set. The command however has to
// keep track of the item removed, so the state inside it has to be of type T.
Command <T> removeCmd = new Command <T>(() => this.PerformRemoveItem(index), () => this[index], i => this.PerformInsertItem(index, i), _cachedCommandDescriptions[ListCommandType.RemoveItem]);
CommandQueueManagerSingleton.GetInstance().EnqueueAndRunCommand(removeCmd);
}
public void CancelableEventsOnCommandifiedListTests()
{
CommandifiedList <int> list = new CommandifiedList <int>()
{
1, 2, 3
};
EventHandler <CancelableListModificationEventArgs <int> > cancelableHandler = delegate(object sender, CancelableListModificationEventArgs <int> e) { e.Cancel = true; };
list.ElementAdding += cancelableHandler;
list.ElementRemoving += cancelableHandler;
list.ListClearing += cancelableHandler;
// reset command queue manager, so it will only undo commands issued after this reset
CommandQueueManagerSingleton.GetInstance().ResetActiveCommandQueue();
list.Add(4);
Assert.AreEqual(3, list.Count);
Assert.IsFalse(list.Contains(4));
// undo shouldn't have any effect
CommandQueueManagerSingleton.GetInstance().UndoLastCommand();
Assert.AreEqual(3, list.Count);
Assert.IsFalse(list.Contains(4));
list.Clear();
Assert.AreEqual(3, list.Count);
// undo shouldn't have any effect
CommandQueueManagerSingleton.GetInstance().UndoLastCommand();
Assert.AreEqual(3, list.Count);
list.Remove(1);
Assert.AreEqual(3, list.Count);
Assert.IsTrue(list.Contains(1));
// undo shouldn't have any effect
CommandQueueManagerSingleton.GetInstance().UndoLastCommand();
Assert.AreEqual(3, list.Count);
Assert.IsTrue(list.Contains(1));
list.ElementAdding -= cancelableHandler;
list.ElementRemoving -= cancelableHandler;
list.ListClearing -= cancelableHandler;
list.Add(4);
Assert.AreEqual(4, list.Count);
Assert.IsTrue(list.Contains(4));
list.Remove(1);
Assert.AreEqual(3, list.Count);
Assert.IsFalse(list.Contains(1));
list.Clear();
Assert.AreEqual(0, list.Count);
}
/// <summary>
/// Removes all elements from the <see cref="T:System.Collections.ObjectModel.Collection`1"/>.
/// </summary>
protected override void ClearItems()
{
if (!this.SuppressEvents)
{
CancelableListModificationEventArgs <T> eventArgs = new CancelableListModificationEventArgs <T>();
this.ListClearing.RaiseEvent(this, eventArgs);
if (eventArgs.Cancel)
{
return;
}
}
// create a command which stores the current state into a temp collection and then clears this collection.
Command <Collection <T> > clearCmd = new Command <Collection <T> >(() => this.PerformClearItems(), () => this.GetCurrentState(), c => this.SetCurrentState(c), "Clear this instance");
CommandQueueManagerSingleton.GetInstance().EnqueueAndRunCommand(clearCmd);
}
/// <summary>
/// Replaces the element at the specified index.
/// </summary>
/// <param name="index">The zero-based index of the element to replace.</param>
/// <param name="item">The new value for the element at the specified index. The value can be null for reference types.</param>
/// <exception cref="T:System.ArgumentOutOfRangeException">
/// <paramref name="index"/> is less than zero.-or-<paramref name="index"/> is greater than <see cref="P:System.Collections.ObjectModel.Collection`1.Count"/>.</exception>
protected override void SetItem(int index, T item)
{
VerifyIndex(index);
if (!this.SuppressEvents)
{
CancelableListModificationEventArgs <T> eventArgs = new CancelableListModificationEventArgs <T>(item);
this.ElementRemoving.RaiseEvent(this, eventArgs);
if (eventArgs.Cancel)
{
return;
}
this.ElementAdding.RaiseEvent(this, eventArgs);
if (eventArgs.Cancel)
{
return;
}
}
// Create a command which stores the current item at index and sets item as the new item at index.
Command <T> setCmd = new Command <T>(() => this.PerformSetItem(index, item), () => this[index], i => this.PerformSetItem(index, i), _cachedCommandDescriptions[ListCommandType.SetItem]);
CommandQueueManagerSingleton.GetInstance().EnqueueAndRunCommand(setCmd);
}
/// <summary>
/// Inserts an element into the <see cref="T:System.Collections.ObjectModel.Collection`1"/> at the specified index.
/// </summary>
/// <param name="index">The zero-based index at which <paramref name="item"/> should be inserted.</param>
/// <param name="item">The object to insert. The value can be null for reference types.</param>
/// <exception cref="T:System.ArgumentOutOfRangeException">
/// <paramref name="index"/> is less than zero.-or-<paramref name="index"/> is greater than <see cref="P:System.Collections.ObjectModel.Collection`1.Count"/>.</exception>
protected override void InsertItem(int index, T item)
{
// index isn't verified as index can be invalid (in the case of an append).
if (!this.SuppressEvents)
{
CancelableListModificationEventArgs <T> eventArgs = new CancelableListModificationEventArgs <T>(item);
this.ElementAdding.RaiseEvent(this, eventArgs);
if (eventArgs.Cancel)
{
return;
}
}
// we can skip the ceremony of going through the command structure if that's disabled.
if (CommandQueueManagerSingleton.GetInstance().IsInNonUndoablePeriod)
{
this.PerformInsertItem(index, item);
}
else
{
// create a command which simply inserts the item at the given index and as undo function removes the item at the index specified.
Command <T> .DoNow(() => this.PerformInsertItem(index, item), () => this.PerformRemoveItem(index), "Insert an item");
}
}
