title: Pass command parameter to method in ViewModel in WPF?
body: <p>I am trying to pass <code>CommandParameter</code> to the method in my <code>ViewModel</code>.
  How to do this?</p>
  
  <pre><code>private void Open(object sender)
  {
      if (sender==this.objMainWindow.btnHistory)
      {
          objMainWindow.Container.Child = objHistory;
      }
  
      if (sender == this.objMainWindow.btnNew_Item)
      {
          objMainWindow.Container.Child = objNewItem;
      }
  
      if (sender == this.objMainWindow.btnSide_Effects)
      {
          objMainWindow.Container.Child = objSideEffect;
      }
  }
  </code></pre>
  
  <p>This is my meyhod in <code>ViewModel</code> that I want to pass <code>CommandParameter</code>. I use <code>CommandParameter</code> for button.</p>