Vb.net time delay happening before it is supposed to do -

i want happen @ same time pause in code happens before button changes color how make happens afterwards.

public class form1 private sub button10_click(sender object, e eventargs) handles button10.click     randomize()      dim buttonnum integer = cint(int((9 * rnd()) + 1))      select case buttonnum         case "1"             button1.backcolor = color.blue         case "2"             button2.backcolor = color.red         case "3"             button3.backcolor = color.orange         case "4"             button4.backcolor = color.yellow         case "5"             button5.backcolor = color.pink         case "6"             button6.backcolor = color.purple         case "7"             button7.backcolor = color.brown         case "8"             button8.backcolor = color.violet         case "9"             button9.backcolor = color.green     end select      threading.thread.sleep(1000)     msgbox("i")    end sub 

end class

try adding application.doevents after selection finishes. know works message box text, may update color too.