/// <summary>
/// Performs the 'Redo' action of the most recently undone command. This command will
/// then be moved back to the undo stack so it can later be undone again.
/// </summary>
public void RedoCommand()
{
if (mRedoStack.Count == 0)
{
throw new InvalidOperationException("There are no commands to be redone");
}
IVEFCommand cmd = mRedoStack.Pop();
cmd.Redo();
mUndoStack.Push(cmd);
FireStateChanged();
}
/// <summary>
/// Undoes the top most command on the undo stack and removes it from the system. The command
/// does not transfer to the redo stack.
/// </summary>
public void UndoAndPopCommand()
{
if (mUndoStack.Count == 0)
{
throw new InvalidOperationException("There are no commands to be undone");
}
IVEFCommand cmd = mUndoStack.Pop();
cmd.Undo();
cmd.Dispose();
// NOTE: We do not push the command onto the redo stack. It just vanishes
FireStateChanged();
}
/// <summary>
/// Adds the given command onto the undo/redo stacks. This will clear any redo commands
/// since the state path has been altered before these commands were originally executed.
/// This may potentially remove elements from the bottom of the undo stack if adding this
/// command will exceed the maximum capacity of the system
/// </summary>
/// <param name="cmd">The command to add to the system</param>
public void AddCommand(IVEFCommand cmd)
{
mRedoStack.Clear();
if (mUndoStack.Count == mMaxCommands)
{
ReduceStackFromBottom(mUndoStack, 1);
}
mUndoStack.Push(cmd);
//if(cmd.CanExecute(null))
//{
// cmd.Execute(null);
//}
// TODO: Handle the case of a non-undoable command being added
FireStateChanged();
}
