Not able to use canvas function in Delphi 7

问题

I am beginning to learn GDI graphics in Delphi 7. I am having problems in drawing Ellipses , Text etc. on my Main form. Basically I use this code:

     Form1.Canvas.TextOut(10,10,'sss');

Is this Canvas Property required to be associated with the Form? I haven't done any thing like that. Help will be appreciated.

回答1:

Make sure you put all painting code in the form's OnPaint event handler (documentation). This handler is called whenever the form needs to be repainted.

procedure TForm1.FormPaint(Sender: TObject);
begin
Canvas.TextOut(10,10,'sss');
end;

来源：https://stackoverflow.com/questions/7147045/not-able-to-use-canvas-function-in-delphi-7