How to make a mouse follow-up window--simple

Just like QQ pet or Thunder hover window, mouse click down the form to follow the mouse move

The main is two time loading

MouseDown and MouseMove Events

MouseDown event:

1         private int _startx;//mouse point down the coordinates 2         private int _starty; 3         private void Form1_mousedown (object sender, MouseEventArgs e) 4         {5             _startx = e.x;//e is the mouse punctuation event 6             _starty = e.y;7         }

MouseMove Events

1 private void Form1_mousemove (object sender, MouseEventArgs e) 2         {3             if (E.button = = System.Windows.Forms.Mous Ebuttons.left) 4             {5 this                 . Left + = e.x-_startx;//minus the coordinates of the mouse point is the window that moves the position under the point 6 this                 . Top + = e.y-_starty;7             }8         }

If inside

E.button = = System.Windows.Forms.MouseButtons.Left Perform a move event when the left mouse button is down
If you do not add---the action of the form will be performed when the mouse moves over the form

How to make a mouse follow-up window--simple