How do I clear a panel from old drawing

Question

0.00/5 (No votes)

See more:

hi,

I have a menu item Clear which should clear the panel from all drawing.
There is no controls existing in this Panel only lines.

I thought it should be easy to clear the Panel from old drawings but it
isn't
I have tried with this code
graphics.Clear(drawingBox1.BackColor);
but the old drawing reback after clearing .

So how can I remove the old drawing and have the Panel as it is when I start
the program.

Posted 9-May-11 11:25am

Member 7909789

Add a Solution

Comments

JOAT-MON 9-May-11 18:02pm

What is your process for drawing in the panel? How you remove the drawing is in part relative to how you put the drawing in there.

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Sergey Alexandrovich Kryukov · Answer 1 · 2011-05-09T17:09:00

First of all, do you draw correctly?

You need to draw on the Panel (or any other Control) handling its event Paint or overriding OnPaint. You need to used the instance of the System.Drawing.Graphics you get from event arguments (in both cases). The call is repeated every time WM_PAINT message is dispatched. I won't happen until the control appears on screen again, after being masked by something else (maybe partially) or minimizing.

Now, what to do it your graphics changes? You simply change some data used in rendering and wait for new WM_PAINT. But how this message can be triggered programmatically (you need change to be immediately displayed)?

Very simple: you need to use System.Windows.Forms.Control.Invalidate! It will work.
To improve performance you can use Invalidate with parameters (Rectangle or Region); it will invalidate only the part of the scene, hopefully the part that has changed.

—SA