Control Painting

One more for you gentlemen (and ladies)...

 

I have a class that accepts a 'canvas' in its constructor (a reference
which is held in the class with the variable '_canvas').  The canvas is
any control that has a Graphics object that can be drawn to (normally, I
use a System.Windows.Forms.Panel object that is placed on a form).   

 

The main method in this class is called 'DrawFigure' and it is intended
to do all the drawing of the 'Figure' the class is working with.

 

I have added several event handlers to the class - probably most
importantly is a handler for the _canvas.Paint event.  And this is where
I lose a bit of understanding.

 

In the event handler I have hooked to _canvas.Paint, I call the
'DrawFigure'method - I don't do anything else.

 

The 'DrawFigure' method looks like...

 

        public void DrawFigure()

        {

 

            _canvas.SuspendLayout ( );

 

            Graphics g = Graphics.FromHwnd ( _canvas.Handle );

 

            g.Clear ( _canvas.BackColor);

            g.TextRenderingHint =
System.Drawing.Text.TextRenderingHint.AntiAlias;

            g.TextContrast = 12;

 

// blah, blah, blah code to draw what I want...

 

            _canvas.ResumeLayout ( );

 

            // Always dispose fo the Graphics object.

            g.Dispose ( );

        }

 

Now to my question...  I want to use another control for the canvas
(FWIW, it's a Infragistics.UltraGroupBox - not that that should
necessarily matter).  However, I must be doing something screwy with the
painting since my drawing doesn't show up on this new 'canvas' until I
click on a part of it (and then only part of drawing shows).

 

I don't understand the event chain that is going on and what and when I
should probably be painting.  Any suggestions about where to look get my
class drawing correctly on this new 'canvas'?

 

Peter