title: How to delete a Line in MFC
body: <p>I'm writing an MFC Application like Paint. 
  I draw a line (by hold and move the mouse) in two steps:</p>
  
  <p><em>Step 1: Handle WM_LBUTTONDOWN and get startPoint.</em></p>
  
  <p><em>Step 2: Handle WM_MOUSEMOVE (with MK_LBUTTON) to get endPoint, and draw a line from startPoint to endPoint using LineTo() function.</em></p>
  
  <p>But in Step 2, it draws one line when receive WM_MOUSEMOVE, so creates too much lines. I want to delete old line and draw new one in this step. (Only one line is drawn when receive WM_LBUTTONUP).
  Can you help me please. Thank everyone. Sorry if my English is so bad.</p>