user32: Invalidate the listbox in LB_SETCOUNT.

dlls/user32/listbox.c

@@ -1767,6 +1767,8 @@ static LRESULT LISTBOX_SetCount( LB_DESCR *descr, INT count )
             if ((ret = LISTBOX_RemoveItem( descr, (descr->nb_items - 1) )) < 0)
                 return ret;
     }
+
+    InvalidateRect( descr->self, NULL, TRUE );
     return LB_OKAY;
 }
 

dlls/user32/tests/listbox.c

@@ -274,30 +274,42 @@ static LRESULT WINAPI main_window_proc(HWND hwnd, UINT msg, WPARAM wparam, LPARA
     return DefWindowProc(hwnd, msg, wparam, lparam);
 }
 
-static void test_ownerdraw(void)
+static HWND create_parent( void )
 {
     WNDCLASS cls;
-    HWND parent, hLB;
-    INT ret;
-    RECT rc;
+    HWND parent;
+    static ATOM class;
 
-    cls.style = 0;
-    cls.lpfnWndProc = main_window_proc;
-    cls.cbClsExtra = 0;
-    cls.cbWndExtra = 0;
-    cls.hInstance = GetModuleHandle(0);
-    cls.hIcon = 0;
-    cls.hCursor = LoadCursor(0, IDC_ARROW);
-    cls.hbrBackground = GetStockObject(WHITE_BRUSH);
-    cls.lpszMenuName = NULL;
-    cls.lpszClassName = "main_window_class";
-    ok (RegisterClass(&cls), "RegisterClass failed\n");
+    if (!class)
+    {
+        cls.style = 0;
+        cls.lpfnWndProc = main_window_proc;
+        cls.cbClsExtra = 0;
+        cls.cbWndExtra = 0;
+        cls.hInstance = GetModuleHandle(0);
+        cls.hIcon = 0;
+        cls.hCursor = LoadCursor(0, IDC_ARROW);
+        cls.hbrBackground = GetStockObject(WHITE_BRUSH);
+        cls.lpszMenuName = NULL;
+        cls.lpszClassName = "main_window_class";
+        class = RegisterClass( &cls );
+    }
 
     parent = CreateWindowEx(0, "main_window_class", NULL,
                             WS_POPUP | WS_VISIBLE,
                             100, 100, 400, 400,
                             GetDesktopWindow(), 0,
                             GetModuleHandle(0), NULL);
+    return parent;
+}
+
+static void test_ownerdraw(void)
+{
+    HWND parent, hLB;
+    INT ret;
+    RECT rc;
+
+    parent = create_parent();
     assert(parent);
 
     hLB = create_listbox(LBS_OWNERDRAWFIXED | WS_CHILD | WS_VISIBLE, parent);
@@ -1498,6 +1510,41 @@ static void test_listbox_dlgdir(void)
     DestroyWindow(hWnd);
 }
 
+static void test_set_count( void )
+{
+    HWND parent, listbox;
+    LONG ret;
+    RECT r;
+
+    parent = create_parent();
+    listbox = create_listbox( LBS_OWNERDRAWFIXED | LBS_NODATA | WS_CHILD | WS_VISIBLE, parent );
+
+    UpdateWindow( listbox );
+    GetUpdateRect( listbox, &r, TRUE );
+    ok( IsRectEmpty( &r ), "got non-empty rect\n");
+
+    ret = SendMessage( listbox, LB_SETCOUNT, 100, 0 );
+    ok( ret == 0, "got %d\n", ret );
+    ret = SendMessage( listbox, LB_GETCOUNT, 0, 0 );
+    ok( ret == 100, "got %d\n", ret );
+
+    GetUpdateRect( listbox, &r, TRUE );
+    ok( !IsRectEmpty( &r ), "got empty rect\n");
+
+    ValidateRect( listbox, NULL );
+    GetUpdateRect( listbox, &r, TRUE );
+    ok( IsRectEmpty( &r ), "got non-empty rect\n");
+
+    ret = SendMessage( listbox, LB_SETCOUNT, 99, 0 );
+    ok( ret == 0, "got %d\n", ret );
+
+    GetUpdateRect( listbox, &r, TRUE );
+    ok( !IsRectEmpty( &r ), "got empty rect\n");
+
+    DestroyWindow( listbox );
+    DestroyWindow( parent );
+}
+
 START_TEST(listbox)
 {
   const struct listbox_test SS =
@@ -1576,4 +1623,5 @@ START_TEST(listbox)
   test_listbox_item_data();
   test_listbox_LB_DIR();
   test_listbox_dlgdir();
+  test_set_count();
 }