/// <summary>
/// Executes command, pushes it into the undo stack
/// and clears the redo stack
/// </summary>
public void Execute(ICommand command)
{
command.Execute();
UndoStack.Push(command);
RedoStack.Clear();
if (UndoStack.Count == 1)
{
CanUndoChanged?.Invoke(true, null);
}
CanRedoChanged?.Invoke(false, null);
}
/// <summary>
/// Redoes command
/// </summary>
public void Redo()
{
if (!CanRedo)
{
return;
}
var command = RedoStack.Pop();
command.Execute();
UndoStack.Push(command);
if (!CanRedo)
{
CanRedoChanged?.Invoke(false, null);
}
if (UndoStack.Count == 1)
{
CanUndoChanged?.Invoke(true, null);
}
}
private void UndoStack_HasItemsChanged(object sender, EventArgs e)
{
CanUndoChanged?.Invoke(this, new EventArgs());
}
/// <summary>
/// 触发可撤销/重做状态变更事件;
/// </summary>
protected void RaiseCanUndoRedoChanged()
{
CanRedoChanged?.Invoke(this, new CanRedoChangedEventArgs(CanRedo));
CanUndoChanged?.Invoke(this, new CanUndoChangedEventArgs(CanUndo));
}
private void UndoService_CanUndoChanged(object sender, EventArgs e)
{
CanUndoChanged?.Invoke(this, e);
}
} // proc Redo
private void RaiseCanUndo()
=> CanUndoChanged?.Invoke(this, EventArgs.Empty);
private void UndoRedoHandler_CanUndoChanged(object sender, EventArgs e)
{
CanUndoChanged?.Invoke(null, EventArgs.Empty);
}