c# pass through mouse events to parent control

Environment: .NET Framework 2.0, VS 2008, C#

I am trying to create a subclass of certain .NET controls (label, panel) that will pass through certain mouse events (MouseDown, MouseMove, MouseUp) to its parent control (or alternatively to the toplevel form). I can do this by creating handlers for these events in instances of the standard controls, e.g.

public class theForm : Form
{
    private Label theLabel;

    private void InitializeComponent()
    {
        theLabel = new Label();
        theLabel.MouseDown += new MouseEventHandler(theLabel_MouseDown);
    }

    private void theLabel_MouseDown(object sender, MouseEventArgs e)
    {
        int xTrans = e.X + this.Location.X;
        int yTrans = e.Y + this.Location.Y;
        MouseEventArgs eTrans = new MouseEventArgs(e.Button, e.Clicks, xTrans, yTrans, e.Delta);
        this.OnMouseDown(eTrans);
    }
}

I cannot move the event handler into a subclass of the control, because the methods that raise the events in the parent control are protected and I don't have a qualifier for the parent control:

Error 1 Cannot access protected member 'System.Windows.Forms.Control.OnMouseDown(System.Windows.Forms.MouseEventArgs)' via a qualifier of type 'System.Windows.Forms.Control'; the qualifier must be of type 'theProject.NoCaptureLabel' (or derived from it) C:\Documents and Settings\Me\My Documents\Visual Studio 2008\Projects\theProject\NoCaptureControls.cs 30 22 theProject

I am looking into overriding the WndProc() method of the control in my subclass but hoping someone can give me a cleaner solution. TIA

From stackoverflow

• You need to write a public/protected method in your base class which will raise the event for you. Then call this method from the derived class.

  OR

  Is this what you want?

  public class MyLabel : Label
  {
      protected override void OnMouseDown(MouseEventArgs e)
      {
          base.OnMouseDown(e);
          //Do derived class stuff here
      }
  }
  

  GentlemanCoder : I don't think so. OnMouseDown *raises* the event, it does not handle it. I need an event handler that passes the event to it's parent. And I can't do your first suggestion b/c the base class is a standard Windows control, not a class that I wrote.

• The WS_EX_TRANSPARENT extended window style actually does this (it's what in-place tooltips use). You might want to consider applying this style rather than coding lots of handlers to do it for you.

  To do this, override the CreateParams method:

  protected override CreateParams CreateParams
  {
    get
    {
      CreateParams cp=base.CreateParams;
      cp.ExStyle|=0x00000020; //WS_EX_TRANSPARENT
      return cp;
    }
  }
  

  For further reading:

  • http://support.microsoft.com/kb/92526
  • http://msdn.microsoft.com/en-us/library/ms632680.aspx
  GentlemanCoder : Thanks for the suggestion. I tried it and it does not work in my case. Perhaps it only works for top level windows?