Draw a rectangle on the MFC dialog box. How can I move the rectangle following the dialog box?

I show the video in the MFC dialog box, and then draw a rectangle in onpaint. Then I drag the dialog box to find that the rectangle is still fixed at the position on the screen and cannot be dragged along with the dialog box, in addition, when another page overwrites the dialog box, the rectangle is drawn to another page, and the dialog box is minimized. The rectangle is also painted on other pages below, with a high finger:

I just want to bind the dialog box to the rectangle drawn. The dialog box moves and the rectangle moves. When the dialog box is overwritten, the rectangle will also be overwritten, as if the rectangle drawn is a part of the dialog box.

 

 

A morning later, I found that the window handle was incorrect.

Http://topic.csdn.net/u/20120322/09/fe369577-bd8c-4b1d-bffe-0cf7dcb26470.html? Seed = 276010730 & R = 77986790 # r_77986790