Environment: .NET Framework 2.0, VS 2008.
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 top-level 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:
Cannot access protected member
System.Windows.Forms.Control.OnMouseDown(System.Windows.Forms.MouseEventArgs)
via a qualifier of typeSystem.Windows.Forms.Control
; the qualifier must be of typeTheProject.NoCaptureLabel
(or derived from it).
I am looking into overriding the WndProc
method of the control in my sub-class, but hopefully someone can give me a cleaner solution.
Best Answer
Yes. After a lot of searching, I found the article "Floating Controls, tooltip-style", which uses
WndProc
to change the message fromWM_NCHITTEST
toHTTRANSPARENT
, making theControl
transparent to mouse events.To achieve that, create a control inherited from
Label
and simply add the following code.I have tested this in Visual Studio 2010 with .NET Framework 4 Client Profile.