Command pattern

Command pattern

• CWinKY

  I am not sure if this is what you want:
  If you have a custom control to handle Undo/Redo commands, you have to register the command bindings.
  
  
  static MyCustomControl()
  {
  CommandManager.RegisterClassCommandBinding(typeof(MyCustomControl), new CommandBinding(ApplicationCommands.Undo, UndoCommand));
  }
  
  
  private static void UndoCommand(object target, ExecutedRoutedEventArgs e)
  {
  MyCustomControl myControl = target as MyCustomControl;
  ...
  }
  
  
  

• Scot5691

  I think I found a solution. You can download it from my blog:

  http://blogs.infosupport.com/ernow/archive/2006/02/27/3961.aspx

  Let me know what you think.

  Regards

  
  

• Paul Dimitrov

  This is not what I am looking for. But your post brought me back on trail!

  I know how to how to setup commands and create my own.

  My problem is building a Undo/Redo stack without repeating the same code in my commandhandlers.

  Here's what I would like:

  class CustomCommandBindingCollection : CommandBindingCollection
  {
    private Stack<UndoRecord> _undoStack = new Stack<UndoRecord>();
    public CustomCommandBinding()
    {
      this.Executed += ....(this.CommandExecuted);
    }

    void CommandExecuted(object source, ExecutedRoutedEventArgs e)
    {
      switch(e.command)
      {
        select:
        _undoStack.Push(new DeselectRecord(......));
      }
  }

  You see, in the CommandPattern there is something called a CommandManager (NOT the CommandManager from System.Windows.Input as your post made me realize) all calls execute via that manager so that is the perfect place to build the Undo/Redo stack.

  Perhaps Microsoft didn't implement the Command pattern afterall... I hope they thought of a way of how to implement is functionality anyway...

  Cheers

  
  

• amcclendon

  If you don't have a custom control but you want to handle the commands at page/window level
  you can do:
  <Page.CommandBindings>
  <CommandBinding Command="ApplicationCommands.Undo" Executed="UndoCommand"/>
  </Page.CommandBindings>
  
  and in code (note that in this case the handle doesn't need to be static)
  private void UndoCommand(object target, ExecutedRoutedEventArgs e)
  {
  ...
  }
  
  
  
• Command pattern