Windows API one-day training (8) updatewindow Function

The updatewindow function is the customer area of the update window. It is mainly implemented by sending the wm_paint message.
 
The function declaration is as follows:
Winuserapi
Bool
Winapi
Updatewindow (
_ In hwnd );
HwndIs the window handle to update the window client area.
 
An example of calling this function is as follows:
#001 bool initinstance (hinstance, int ncmdshow)
#002 {
#003 hwnd;
#004
#005 hinst = hinstance; // Save the instance handle to the global variable.
#006
#007 hwnd = createwindow (szwindowclass,
#008 sztitle,
#009 ws_overlappedwindow,
#010 cw_usedefault,
#011 0,
#012 cw_usedefault,
#013 0,
#014 null,
#015 null,
#016 hinstance,
#017 null );
#018
#019 if (! Hwnd)
#020 {
#021 return false;
#022}
#023
#024 showwindow (hwnd, ncmdshow );
#025 updatewindow (hwnd );
#026
#027 //
#028 // Cai junsheng 2007/07/14
#029 // display window test.
#030 MessageBox (null, _ T ("maximize"), _ T ("test"), mb_ OK );
#031
#032 // the display window is maximized.
#033 showwindow (hwnd, sw_showmaximized );
#034
#035
#036 MessageBox (null, _ T ("original location"), _ T ("test"), mb_ OK );
#037
#038 // the original position of the display window is displayed.
#039 showwindow (hwnd, sw_shownormal );
#040
#041
#042 return true;
#043}
Row 3 calls the updatewindow function to update the customer zone of the window.
 
Generally, after creating a window, you must call the updatewindow function to update the display of the window's customer area. Otherwise, it will be messy.