c# - Lines not drawing to picture box every time -

when code runs 1/3 of time draw properly, rest not draw of lines.

pen pen = new pen(color.black);         graphics graphics = mainfrm.hangmanimage.creategraphics();         switch (noofguesses)         {             case 1://bottom left leg                 graphics.drawline(pen, 15, 60, 40, 60);                 break;             case 2://bottom right leg                 graphics.drawline(pen, 40, 60, 55, 60);                 break;             case 3://middle stock                 graphics.drawline(pen, 34, 20, 34, 60);                 break;             case 4: //top line                 graphics.drawline(pen, 34, 20, 55, 20);                 break;             case 5: //rope                 graphics.drawline(pen, 55, 20, 55, 25);                 break;             case 6: //head                 graphics.drawellipse(pen, (new rectangle { x=52, y=25, height=5, width=5 }));                 break;             case 7: //body                 graphics.drawline(pen, 55, 30, 55, 35);                 break;         }         pen.dispose();         graphics.dispose(); 

not enough information sure, however, first make sure variable 'noofguesses' value between 1-7, value of 0 or 8 end doing nothing. second, add 'default' case in case 'noofguesses' out of range reason , have draw line.