comctl32/monthcal: Changing MCS_MULTISELECT isn't allowed after creation, set…

dlls/comctl32/monthcal.c

@@ -1937,6 +1937,24 @@ static INT MONTHCAL_StyleChanged(MONTHCAL_INFO *infoPtr, WPARAM wStyleType,
     return 0;
 }
 
+static INT MONTHCAL_StyleChanging(MONTHCAL_INFO *infoPtr, WPARAM wStyleType,
+                                  STYLESTRUCT *lpss)
+{
+    TRACE("(styletype=%lx, styleOld=0x%08x, styleNew=0x%08x)\n",
+          wStyleType, lpss->styleOld, lpss->styleNew);
+
+    /* block MCS_MULTISELECT change */
+    if ((lpss->styleNew ^ lpss->styleOld) & MCS_MULTISELECT)
+    {
+        if (lpss->styleOld & MCS_MULTISELECT)
+            lpss->styleNew |= MCS_MULTISELECT;
+        else
+            lpss->styleNew &= ~MCS_MULTISELECT;
+    }
+
+    return 0;
+}
+
 /* FIXME: check whether dateMin/dateMax need to be adjusted. */
 static LRESULT
 MONTHCAL_Create(HWND hwnd, LPCREATESTRUCTW lpcs)
@@ -1965,7 +1983,7 @@ MONTHCAL_Create(HWND hwnd, LPCREATESTRUCTW lpcs)
   infoPtr->firstDayHighWord = FALSE;
   MONTHCAL_SetFirstDayOfWeek(infoPtr, -1);
 
-  infoPtr->maxSelCount   = 7;
+  infoPtr->maxSelCount   = (infoPtr->dwStyle & MCS_MULTISELECT) ? 7 : 1;
   infoPtr->monthRange    = 3;
   infoPtr->monthdayState = Alloc(infoPtr->monthRange * sizeof(MONTHDAYSTATE));
   infoPtr->titlebk       = comctl32_color.clrActiveCaption;
@@ -2131,6 +2149,9 @@ MONTHCAL_WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
   case WM_STYLECHANGED:
     return MONTHCAL_StyleChanged(infoPtr, wParam, (LPSTYLESTRUCT)lParam);
 
+  case WM_STYLECHANGING:
+    return MONTHCAL_StyleChanging(infoPtr, wParam, (LPSTYLESTRUCT)lParam);
+
   default:
     if ((uMsg >= WM_USER) && (uMsg < WM_APP) && !COMCTL32_IsReflectedMessage(uMsg))
       ERR( "unknown msg %04x wp=%08lx lp=%08lx\n", uMsg, wParam, lParam);

dlls/comctl32/tests/monthcal.c

@@ -580,6 +580,14 @@ static LRESULT WINAPI monthcal_subclass_proc(HWND hwnd, UINT message, WPARAM wPa
     msg.lParam = lParam;
     add_message(sequences, MONTHCAL_SEQ_INDEX, &msg);
 
+    /* some debug output for style changing */
+    if ((message == WM_STYLECHANGING ||
+         message == WM_STYLECHANGED) && lParam)
+    {
+        STYLESTRUCT *style = (STYLESTRUCT*)lParam;
+        trace("\told style: 0x%08x, new style: 0x%08x\n", style->styleOld, style->styleNew);
+    }
+
     defwndproc_counter++;
     ret = CallWindowProcA(info->oldproc, hwnd, message, wParam, lParam);
     defwndproc_counter--;
@@ -1302,8 +1310,33 @@ static void test_monthcal_maxselday(void)
 {
     int res;
     HWND hwnd;
+    DWORD style;
+
+    hwnd = create_monthcal_control(0);
+    /* if no style specified default to 1 */
+    res = SendMessage(hwnd, MCM_GETMAXSELCOUNT, 0, 0);
+    expect(1, res);
+
+    /* try to set style */
+    style = GetWindowLong(hwnd, GWL_STYLE);
+    SetWindowLong(hwnd, GWL_STYLE, style | MCS_MULTISELECT);
+    style = GetWindowLong(hwnd, GWL_STYLE);
+    ok(!(style & MCS_MULTISELECT), "Expected MCS_MULTISELECT not to be set\n");
+    DestroyWindow(hwnd);
 
     hwnd = create_monthcal_control(MCS_MULTISELECT);
+    /* try to remove style */
+    style = GetWindowLong(hwnd, GWL_STYLE);
+    SetWindowLong(hwnd, GWL_STYLE, style & ~MCS_MULTISELECT);
+    style = GetWindowLong(hwnd, GWL_STYLE);
+    ok(style & MCS_MULTISELECT, "Expected MCS_MULTISELECT to be set\n");
+    DestroyWindow(hwnd);
+
+    hwnd = create_monthcal_control(MCS_MULTISELECT);
+
+    /* default width is a week */
+    res = SendMessage(hwnd, MCM_GETMAXSELCOUNT, 0, 0);
+    expect(7, res);
 
     flush_sequences(sequences, NUM_MSG_SEQUENCES);