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Hello people,
i am doing drawings on dialof in MFC vc++.

i am drawing lines as per the different inputs i am getting from the serial.

now i want to clear the drawings when i get another input.

What I have tried:


CPen lDot(PS_DASH, 2, RGB(255, 255, 255));


Here a,b,c,d are my different inputs which i am getting from the serial communication.
at each input i want to clear the older drawings and draw a new lines with new data.

is the group box in which i am drawing lines in dialog.
Updated 1-Aug-18 21:34pm

GetDlgItem(IDC_STATICDISPLAY)->Invalidate( true );

That will cause the group box to be erased and redrawn. Erased means the default background will be drawn for the control.
Member 12533122 2-Aug-18 1:40am
GetDlgItem(IDC_STATICDISPLAY)->Invalidate( true );

THIS IS NOT WORKING. its still not clear the old drawing.
Jochen Arndt 2-Aug-18 3:02am
Call GetDlgItem(IDC_STATICDISPLAY)->UpdateWindow() afterwards to force redrawing.
If the control is completly owner drawn that you should use FillRect with your bckground color at first draw call.

And I would suggest that you store the Windows-handle of the control and other constant objects (like the pen) as member variables to improve performance.
Member 12533122 3-Aug-18 7:27am
i have done the same for temporary. i am drawing rect with background color and then draws the lines.
so like that every time i first draw blank rect and then draw a lines on it.

it helps me for now.

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