title: How to draw rectangle on MouseDown/Move c#
body: <p>I am not quite sure how to draw a Rectangle (not filled) when I drag my mousedown while left clicking the mouse.</p>
  
  <p>I have this so far</p>
  
  <pre><code>            private void canevas_MouseDown( object sender , MouseEventArgs e )
              {
                      if( e.Button == MouseButtons.Left )
                      {
                              _topLeft = new Point( e.X , e.Y );
                              _drawing = true;
                      }
              }
  
              private void canevas_MouseMove( object sender , MouseEventArgs e )
              {
                      if( _drawing )
                      {
                              Rectangle rec = new Rectangle( _topLeft.X , _topLeft.Y , ( e.X - _topLeft.X ) , ( e.Y - _topLeft.Y ) );
                              canevas.CreateGraphics().DrawRectangle( Pens.Black , rec );
                      }
              }
  </code></pre>
  
  <p>But the problems it that I dont want all the rectangles to show up</p>