GDI+ application: write text over existing one

Pavel

Hello,

In my GDI+ application I need to change dynamically some texts. If just write new string over existing one, 2 strings will be superposed.
So, one should to remove old string before to write the new one.
Only solution I found for the moment is to invalidate the specific region of the control, where graphics are drawn (Panel in my case).
It works perfectly - after applying pnl_Graphics.Invalidate(rect1), all graphics inside of rect1 disappear.

But when I draw new text in the same region, it doesn't appear !

What could be a workaround ?

Thanks in advance.

Pavel.

3 Replies

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Pavel14y ago
I lloked through some examples when graphics are drawn inside of Paint event handlers. All have fixed code - i.e. when invoked they do the same job. In my case the fashion of how redraw a panel (or rather region of panel) depends on algoritm.

So coding of Paint event cannot be "rigid".
If my understandig is correct if one need to redraw a Control (e.g. Panel), he should call Invalidate method (optionally with limits) - pnl.Invalidate();

Invalidate calls Paint event, that has following interface:
private void pnl_Paint(object sender, PaintEventArgs e)

How to pass some parameters in order to pnl_Paint know what to do ?

Is there some other workaround - without using of Paint handler ?
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Pavel14y ago
Hi Manesh,

Thanks for response. There is no any event for redrawing. Until I've met this problem, I don't need it. I drawn all my graphics using dc.DrawRectangle, dc.DrawEllips, dc.DrawString, etc. (where dc - Graphics object, associated with Panel) and all objects are drawn perfectly.

Regards.
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Mahesh Chand14y ago
What even of Form are you using the redraw the text? It must be Form's paint or any control's paint event. If you are drawing on a button click or some other events, you must force the paint method execution.
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