Simplify changing window styles in wxMSW code

Add wxMSWWinStyleUpdater and wxMSWWinExStyleUpdater helper classes which
allow writing code changing GWL_STYLE and GWL_EXSTYLE bits,
respectively, in a shorter and more clear way.

There should be no real changes in behaviour.

include/wx/msw/private.h

@@ -978,19 +978,9 @@ inline bool wxStyleHasBorder(long style)
                      wxSUNKEN_BORDER | wxDOUBLE_BORDER)) != 0;
 }
 
-inline long wxGetWindowExStyle(const wxWindowMSW *win)
-{
-    return ::GetWindowLong(GetHwndOf(win), GWL_EXSTYLE);
-}
-
 inline bool wxHasWindowExStyle(const wxWindowMSW *win, long style)
 {
-    return (wxGetWindowExStyle(win) & style) != 0;
+    return (::GetWindowLong(GetHwndOf(win), GWL_EXSTYLE) & style) != 0;
-}
-
-inline long wxSetWindowExStyle(const wxWindowMSW *win, long style)
-{
-    return ::SetWindowLong(GetHwndOf(win), GWL_EXSTYLE, style);
 }
 
 // Common helper of wxUpdate{,Edit}LayoutDirection() below: sets or clears the

include/wx/msw/private/winstyle.h

@@ -0,0 +1,134 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/msw/private/winstyle.h
+// Purpose:     Small helper class for updating MSW windows style
+// Author:      Vadim Zeitlin
+// Created:     2017-12-09
+// Copyright:   (c) 2017 Vadim Zeitlin <vadim@wxwidgets.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_MSW_PRIVATE_WINSTYLE_H_
+#define _WX_MSW_PRIVATE_WINSTYLE_H_
+
+// ----------------------------------------------------------------------------
+// wxMSWWinLongUpdater
+// ----------------------------------------------------------------------------
+
+/*
+    This class is not used directly, but either as wxMSWWinStyleUpdater or
+    wxMSWWinExStyleUpdater, both of which inherit from it and can be used like
+    this:
+
+    void SomeFunction()
+    {
+        wxMSWWinStyleUpdater updateStyle(GetHwndOf(m_win));
+        if ( some-condition )
+            updateStyle.TurnOn(XX_YYY);
+
+        // Style update happens here implicitly -- or call Apply().
+    }
+ */
+class wxMSWWinLongUpdater
+{
+public:
+    // Get the current style.
+    LONG_PTR Get() const
+    {
+        return m_styleCurrent;
+    }
+
+    // Check if the given style bit(s) is (are all) currently turned on.
+    bool IsOn(LONG_PTR style) const
+    {
+        return (m_styleCurrent & style) == style;
+    }
+
+    // Turn on some bit(s) in the style.
+    wxMSWWinLongUpdater& TurnOn(LONG_PTR on)
+    {
+        m_style |= on;
+        return *this;
+    }
+
+    // Turn off some bit(s) in the style.
+    wxMSWWinLongUpdater& TurnOff(LONG_PTR off)
+    {
+        m_style &= ~off;
+        return *this;
+    }
+
+    // Turn some bit(s) on or off depending on the condition.
+    wxMSWWinLongUpdater& TurnOnOrOff(bool cond, LONG_PTR style)
+    {
+        return cond ? TurnOn(style) : TurnOff(style);
+    }
+
+    // Perform the style update (only if necessary, i.e. if the style really
+    // changed).
+    //
+    // Notice that if this method is not called, it's still done from the dtor,
+    // so it's just a convenient way to do it sooner and avoid having to create
+    // a new scope for ensuring that the dtor runs at the right place, but
+    // otherwise is equivalent to do this.
+    bool Apply()
+    {
+        if ( m_style == m_styleCurrent )
+            return false;
+
+        ::SetWindowLongPtr(m_hwnd, m_gwlSlot, m_style);
+
+        m_styleCurrent = m_style;
+
+        return true;
+    }
+
+    ~wxMSWWinLongUpdater()
+    {
+        Apply();
+    }
+
+protected:
+    // Create the object for updating the style or extended style of the given
+    // window.
+    //
+    // Ctor is protected, this class can only be used as wxMSWWinStyleUpdater
+    // or wxMSWWinExStyleUpdater.
+    wxMSWWinLongUpdater(HWND hwnd, int gwlSlot)
+        : m_hwnd(hwnd),
+          m_gwlSlot(gwlSlot),
+          m_styleCurrent(::GetWindowLongPtr(hwnd, gwlSlot)),
+          m_style(m_styleCurrent)
+    {
+    }
+
+private:
+    const HWND m_hwnd;
+    const int m_gwlSlot;
+
+    LONG_PTR m_styleCurrent;
+    LONG_PTR m_style;
+
+    wxDECLARE_NO_COPY_CLASS(wxMSWWinLongUpdater);
+};
+
+// A variant of wxMSWWinLongUpdater which updates the extended style.
+class wxMSWWinStyleUpdater : public wxMSWWinLongUpdater
+{
+public:
+    explicit wxMSWWinStyleUpdater(HWND hwnd)
+        : wxMSWWinLongUpdater(hwnd, GWL_STYLE)
+    {
+    }
+};
+
+// A variant of wxMSWWinLongUpdater which updates the extended style.
+class wxMSWWinExStyleUpdater : public wxMSWWinLongUpdater
+{
+public:
+    explicit wxMSWWinExStyleUpdater(HWND hwnd)
+        : wxMSWWinLongUpdater(hwnd, GWL_EXSTYLE)
+    {
+    }
+};
+
+#endif // _WX_MSW_PRIVATE_WINSTYLE_H_

src/msw/anybutton.cpp

@@ -44,6 +44,7 @@
 #include "wx/stockitem.h"
 #include "wx/msw/private/button.h"
 #include "wx/msw/private/dc.h"
+#include "wx/msw/private/winstyle.h"
 #include "wx/msw/uxtheme.h"
 #include "wx/private/window.h"
 
@@ -387,15 +388,11 @@ void wxMSWButton::UpdateMultilineStyle(HWND hwnd, const wxString& label)
     // have to set it whenever the label becomes multi line as otherwise it
     // wouldn't be shown correctly as we don't use BS_MULTILINE when creating
     // the control unless it already has new lines in its label)
-    long styleOld = ::GetWindowLong(hwnd, GWL_STYLE),
+    wxMSWWinStyleUpdater updateStyle(hwnd);
-         styleNew;
     if ( label.find(wxT('\n')) != wxString::npos )
-        styleNew = styleOld | BS_MULTILINE;
+        updateStyle.TurnOn(BS_MULTILINE);
     else
-        styleNew = styleOld & ~BS_MULTILINE;
+        updateStyle.TurnOff(BS_MULTILINE);
-
-    if ( styleNew != styleOld )
-        ::SetWindowLong(hwnd, GWL_STYLE, styleNew);
 }
 
 wxSize wxMSWButton::GetFittingSize(wxWindow *win,
@@ -1177,11 +1174,7 @@ void wxAnyButton::MakeOwnerDrawn()
     if ( !IsOwnerDrawn() )
     {
         // make it so
-        // note that BS_OWNERDRAW is not independent from other style bits
+        wxMSWWinStyleUpdater(GetHwnd()).TurnOff(BS_TYPEMASK).TurnOn(BS_OWNERDRAW);
-        long style = GetWindowLong(GetHwnd(), GWL_STYLE);
-        style &= ~(BS_3STATE | BS_AUTO3STATE | BS_AUTOCHECKBOX | BS_AUTORADIOBUTTON | BS_CHECKBOX | BS_DEFPUSHBUTTON | BS_GROUPBOX | BS_PUSHBUTTON | BS_RADIOBUTTON | BS_PUSHLIKE);
-        style |= BS_OWNERDRAW;
-        SetWindowLong(GetHwnd(), GWL_STYLE, style);
     }
 }
 

src/msw/combobox.cpp

@@ -40,6 +40,7 @@
 #include "wx/clipbrd.h"
 #include "wx/wupdlock.h"
 #include "wx/msw/private.h"
+#include "wx/msw/private/winstyle.h"
 
 #if wxUSE_UXTHEME
     #include "wx/msw/uxtheme.h"
@@ -711,11 +712,10 @@ void wxComboBox::SetLayoutDirection(wxLayoutDirection dir)
         }
         else
         {
-            LONG_PTR style = ::GetWindowLongPtr(GetEditHWND(), GWL_STYLE);
+            wxMSWWinStyleUpdater styleUpdater(GetEditHWND());
-            if ( !(style & ES_CENTER) )
+            if ( !styleUpdater.IsOn(ES_CENTER) )
             {
-                style &= ~ES_RIGHT;
+                styleUpdater.TurnOff(ES_RIGHT);
-                ::SetWindowLongPtr(GetEditHWND(), GWL_STYLE, style);
             }
         }
     }

src/msw/control.cpp

@@ -51,6 +51,7 @@
 #include "wx/msw/uxtheme.h"
 #include "wx/msw/dc.h"          // for wxDCTemp
 #include "wx/msw/ownerdrawnbutton.h"
+#include "wx/msw/private/winstyle.h"
 
 // ----------------------------------------------------------------------------
 // wxWin macros
@@ -421,14 +422,13 @@ bool wxMSWOwnerDrawnButtonBase::MSWIsOwnerDrawn() const
 
 void wxMSWOwnerDrawnButtonBase::MSWMakeOwnerDrawn(bool ownerDrawn)
 {
-    long style = ::GetWindowLong(GetHwndOf(m_win), GWL_STYLE);
+    wxMSWWinStyleUpdater updateStyle(GetHwndOf(m_win));
 
     // note that BS_CHECKBOX & BS_OWNERDRAW != 0 so we can't operate on
     // them as on independent style bits
     if ( ownerDrawn )
     {
-        style &= ~BS_TYPEMASK;
+        updateStyle.TurnOff(BS_TYPEMASK).TurnOn(BS_OWNERDRAW);
-        style |= BS_OWNERDRAW;
 
         m_win->Bind(wxEVT_ENTER_WINDOW,
                     &wxMSWOwnerDrawnButtonBase::OnMouseEnterOrLeave, this);
@@ -448,8 +448,7 @@ void wxMSWOwnerDrawnButtonBase::MSWMakeOwnerDrawn(bool ownerDrawn)
     }
     else // reset to default colour
     {
-        style &= ~BS_OWNERDRAW;
+        updateStyle.TurnOff(BS_OWNERDRAW).TurnOn(MSWGetButtonStyle());
-        style |= MSWGetButtonStyle();
 
         m_win->Unbind(wxEVT_ENTER_WINDOW,
                       &wxMSWOwnerDrawnButtonBase::OnMouseEnterOrLeave, this);
@@ -467,7 +466,7 @@ void wxMSWOwnerDrawnButtonBase::MSWMakeOwnerDrawn(bool ownerDrawn)
                       &wxMSWOwnerDrawnButtonBase::OnFocus, this);
     }
 
-    ::SetWindowLong(GetHwndOf(m_win), GWL_STYLE, style);
+    updateStyle.Apply();
 
     if ( !ownerDrawn )
         MSWOnButtonResetOwnerDrawn();

src/msw/gauge.cpp

@@ -35,6 +35,7 @@
 
 #include "wx/appprogress.h"
 #include "wx/msw/private.h"
+#include "wx/msw/private/winstyle.h"
 
 // ----------------------------------------------------------------------------
 // constants
@@ -190,8 +191,7 @@ void wxGauge::SetIndeterminateMode()
     // Switch the control into indeterminate mode if necessary.
     if ( !IsInIndeterminateMode() )
     {
-        const long style = ::GetWindowLong(GetHwnd(), GWL_STYLE);
+        wxMSWWinStyleUpdater(GetHwnd()).TurnOn(PBS_MARQUEE);
-        ::SetWindowLong(GetHwnd(), GWL_STYLE, style | PBS_MARQUEE);
         ::SendMessage(GetHwnd(), PBM_SETMARQUEE, TRUE, 0);
     }
 }
@@ -200,9 +200,8 @@ void wxGauge::SetDeterminateMode()
 {
     if ( IsInIndeterminateMode() )
     {
-        const long style = ::GetWindowLong(GetHwnd(), GWL_STYLE);
         ::SendMessage(GetHwnd(), PBM_SETMARQUEE, FALSE, 0);
-        ::SetWindowLong(GetHwnd(), GWL_STYLE, style & ~PBS_MARQUEE);
+        wxMSWWinStyleUpdater(GetHwnd()).TurnOff(PBS_MARQUEE);
     }
 }
 

src/msw/headerctrl.cpp

@@ -38,6 +38,7 @@
 #include "wx/msw/wrapcctl.h"
 #include "wx/msw/private.h"
 #include "wx/msw/private/customdraw.h"
+#include "wx/msw/private/winstyle.h"
 
 #ifndef HDM_SETBITMAPMARGIN
     #define HDM_SETBITMAPMARGIN 0x1234
@@ -402,12 +403,8 @@ void wxHeaderCtrl::DoInsertItem(const wxHeaderColumn& col, unsigned int idx)
         }
     }
 
-    long controlStyle = ::GetWindowLong(GetHwnd(), GWL_STYLE);
+    wxMSWWinStyleUpdater(GetHwnd())
-    if ( hasResizableColumns )
+        .TurnOnOrOff(!hasResizableColumns, HDS_NOSIZING);
-        controlStyle &= ~HDS_NOSIZING;
-    else
-        controlStyle |= HDS_NOSIZING;
-    ::SetWindowLong(GetHwnd(), GWL_STYLE, controlStyle);
 }
 
 void wxHeaderCtrl::DoSetColumnsOrder(const wxArrayInt& order)

src/msw/mdi.cpp

@@ -44,6 +44,7 @@
 
 #include "wx/stockitem.h"
 #include "wx/msw/private.h"
+#include "wx/msw/private/winstyle.h"
 
 #include <string.h>
 
@@ -1313,24 +1314,20 @@ bool wxMDIChildFrame::ResetWindowStyle(void *vrect)
     if (!pChild || (pChild == this))
     {
         HWND hwndClient = GetWinHwnd(pFrameWnd->GetClientWindow());
-        DWORD dwStyle = ::GetWindowLong(hwndClient, GWL_EXSTYLE);
+
+        wxMSWWinStyleUpdater updateStyle(hwndClient);
 
         // we want to test whether there is a maximized child, so just set
         // dwThisStyle to 0 if there is no child at all
         DWORD dwThisStyle = pChild
             ? ::GetWindowLong(GetWinHwnd(pChild), GWL_STYLE) : 0;
-        DWORD dwNewStyle = dwStyle;
+        updateStyle.TurnOnOrOff(!(dwThisStyle & WS_MAXIMIZE), WS_EX_CLIENTEDGE);
-        if ( dwThisStyle & WS_MAXIMIZE )
-            dwNewStyle &= ~(WS_EX_CLIENTEDGE);
-        else
-            dwNewStyle |= WS_EX_CLIENTEDGE;
 
-        if (dwStyle != dwNewStyle)
+        if ( updateStyle.Apply() )
         {
             // force update of everything
             ::RedrawWindow(hwndClient, NULL, NULL,
                            RDW_INVALIDATE | RDW_ALLCHILDREN);
-            ::SetWindowLong(hwndClient, GWL_EXSTYLE, dwNewStyle);
             ::SetWindowPos(hwndClient, NULL, 0, 0, 0, 0,
                            SWP_FRAMECHANGED | SWP_NOACTIVATE |
                            SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER |

src/msw/spinctrl.cpp

@@ -36,6 +36,7 @@
 #endif
 
 #include "wx/msw/private.h"
+#include "wx/msw/private/winstyle.h"
 
 #if wxUSE_TOOLTIPS
     #include "wx/tooltip.h"
@@ -549,15 +550,8 @@ void wxSpinCtrl::UpdateBuddyStyle()
     // otherwise this would become impossible and also if we don't use
     // hexadecimal as entering "x" of the "0x" prefix wouldn't be allowed
     // neither then
-    const DWORD styleOld = ::GetWindowLong(GetBuddyHwnd(), GWL_STYLE);
+    wxMSWWinStyleUpdater(GetBuddyHwnd())
-    DWORD styleNew;
+        .TurnOnOrOff(m_min >= 0 && GetBase() == 10, ES_NUMBER);
-    if ( m_min < 0 || GetBase() != 10 )
-        styleNew = styleOld & ~ES_NUMBER;
-    else
-        styleNew = styleOld | ES_NUMBER;
-
-    if ( styleNew != styleOld )
-        ::SetWindowLong(GetBuddyHwnd(), GWL_STYLE, styleNew);
 }
 
 // ----------------------------------------------------------------------------

src/msw/statbmp.cpp

@@ -36,6 +36,7 @@
 
 #include "wx/msw/private.h"
 #include "wx/msw/dib.h"
+#include "wx/msw/private/winstyle.h"
 
 #include "wx/sysopt.h"
 
@@ -312,9 +313,9 @@ void wxStaticBitmap::SetImageNoCopy( wxGDIImage* image)
         }
     }
 #endif // wxUSE_WXDIB
-    LONG style = ::GetWindowLong( (HWND)GetHWND(), GWL_STYLE ) ;
+    wxMSWWinStyleUpdater(GetHwnd())
-    ::SetWindowLong( (HWND)GetHWND(), GWL_STYLE, ( style & ~( SS_BITMAP|SS_ICON ) ) |
+        .TurnOff(SS_BITMAP | SS_ICON)
-                     ( m_isIcon ? SS_ICON : SS_BITMAP ) );
+        .TurnOn(m_isIcon ? SS_ICON : SS_BITMAP);
 
     MSWReplaceImageHandle((WXLPARAM)handle);
 

src/msw/statbox.cpp

@@ -45,6 +45,7 @@
 #include "wx/msw/private.h"
 #include "wx/msw/missing.h"
 #include "wx/msw/dc.h"
+#include "wx/msw/private/winstyle.h"
 
 // the values coincide with those in tmschema.h
 #define BP_GROUPBOX 4
@@ -303,10 +304,10 @@ WXHRGN wxStaticBox::MSWGetRegionWithoutChildren()
             continue;
         }
 
-        LONG style = ::GetWindowLong(child, GWL_STYLE);
+        wxMSWWinStyleUpdater updateStyle(child);
         wxString str(wxGetWindowClass(child));
         str.UpperCase();
-        if ( str == wxT("BUTTON") && (style & BS_GROUPBOX) == BS_GROUPBOX )
+        if ( str == wxT("BUTTON") && updateStyle.IsOn(BS_GROUPBOX) )
         {
             if ( child == GetHwnd() )
                 foundThis = true;
@@ -329,10 +330,9 @@ WXHRGN wxStaticBox::MSWGetRegionWithoutChildren()
         {
             // need to remove WS_CLIPSIBLINGS from all sibling windows
             // that are within this staticbox if set
-            if ( style & WS_CLIPSIBLINGS )
+            if ( updateStyle.IsOn(WS_CLIPSIBLINGS) )
             {
-                style &= ~WS_CLIPSIBLINGS;
+                updateStyle.TurnOff(WS_CLIPSIBLINGS).Apply();
-                ::SetWindowLong(child, GWL_STYLE, style);
 
                 // MSDN: "If you have changed certain window data using
                 // SetWindowLong, you must call SetWindowPos to have the

src/msw/stattext.cpp

@@ -28,6 +28,7 @@
 #endif
 
 #include "wx/msw/private.h"
+#include "wx/msw/private/winstyle.h"
 
 bool wxStaticText::Create(wxWindow *parent,
                           wxWindowID id,
@@ -155,25 +156,21 @@ void wxStaticText::SetLabel(const wxString& label)
         return;
 
 #ifdef SS_ENDELLIPSIS
-    long styleReal = ::GetWindowLong(GetHwnd(), GWL_STYLE);
+    wxMSWWinStyleUpdater updateStyle(GetHwnd());
     if ( HasFlag(wxST_ELLIPSIZE_END) )
     {
         // adding SS_ENDELLIPSIS or SS_ENDELLIPSIS "disables" the correct
         // newline handling in static texts: the newlines in the labels are
         // shown as square. Thus we don't use it even on newer OS when
         // the static label contains a newline.
-        if ( label.Contains(wxT('\n')) )
+        updateStyle.TurnOnOrOff(!label.Contains(wxT('\n')), SS_ENDELLIPSIS);
-            styleReal &= ~SS_ENDELLIPSIS;
-        else
-            styleReal |= SS_ENDELLIPSIS;
-
-        ::SetWindowLong(GetHwnd(), GWL_STYLE, styleReal);
     }
     else // style not supported natively
     {
-        styleReal &= ~SS_ENDELLIPSIS;
+        updateStyle.TurnOff(SS_ENDELLIPSIS);
-        ::SetWindowLong(GetHwnd(), GWL_STYLE, styleReal);
     }
+
+    updateStyle.Apply();
 #endif // SS_ENDELLIPSIS
 
     // save the label in m_labelOrig with both the markup (if any) and
@@ -181,7 +178,7 @@ void wxStaticText::SetLabel(const wxString& label)
     m_labelOrig = label;
 
 #ifdef SS_ENDELLIPSIS
-    if ( styleReal & SS_ENDELLIPSIS )
+    if ( updateStyle.IsOn(SS_ENDELLIPSIS) )
         DoSetLabel(GetLabel());
     else
 #endif // SS_ENDELLIPSIS

src/msw/textentry.cpp

@@ -34,6 +34,7 @@
 #include "wx/dynlib.h"
 
 #include "wx/msw/private.h"
+#include "wx/msw/private/winstyle.h"
 
 #if wxUSE_UXTHEME
     #include "wx/msw/uxtheme.h"
@@ -913,9 +914,7 @@ void wxTextEntry::ForceUpper()
 {
     ConvertToUpperCase();
 
-    const HWND hwnd = GetEditHwnd();
+    wxMSWWinStyleUpdater(GetEditHwnd()).TurnOn(ES_UPPERCASE);
-    const LONG styleOld = ::GetWindowLong(hwnd, GWL_STYLE);
-    ::SetWindowLong(hwnd, GWL_STYLE, styleOld | ES_UPPERCASE);
 }
 
 // ----------------------------------------------------------------------------

src/msw/toplevel.cpp

@@ -41,6 +41,7 @@
 #include "wx/tooltip.h"
 
 #include "wx/msw/private.h"
+#include "wx/msw/private/winstyle.h"
 
 #include "wx/msw/winundef.h"
 #include "wx/msw/missing.h"
@@ -858,14 +859,14 @@ bool wxTopLevelWindowMSW::ShowFullScreen(bool show, long style)
         // zap the frame borders
 
         // save the 'normal' window style
-        m_fsOldWindowStyle = GetWindowLong(GetHwnd(), GWL_STYLE);
+        wxMSWWinStyleUpdater updateStyle(GetHwnd());
+        m_fsOldWindowStyle = updateStyle.Get();
 
         // save the old position, width & height, maximize state
         m_fsOldSize = GetRect();
         m_fsIsMaximized = IsMaximized();
 
         // decide which window style flags to turn off
-        LONG newStyle = m_fsOldWindowStyle;
         LONG offFlags = 0;
 
         if (style & wxFULLSCREEN_NOBORDER)
@@ -876,16 +877,16 @@ bool wxTopLevelWindowMSW::ShowFullScreen(bool show, long style)
         if (style & wxFULLSCREEN_NOCAPTION)
             offFlags |= WS_CAPTION | WS_SYSMENU;
 
-        newStyle &= ~offFlags;
+        updateStyle.TurnOff(offFlags);
 
         // Full screen windows should logically be popups as they don't have
         // decorations (and are definitely not children) and while not using
         // this style doesn't seem to make any difference for most windows, it
         // breaks wxGLCanvas in some cases, see #15434, so just always use it.
-        newStyle |= WS_POPUP;
+        updateStyle.TurnOn(WS_POPUP);
 
         // change our window style to be compatible with full-screen mode
-        ::SetWindowLong(GetHwnd(), GWL_STYLE, newStyle);
+        updateStyle.Apply();
 
         wxRect rect;
 #if wxUSE_DISPLAY
@@ -1137,19 +1138,18 @@ wxMenu *wxTopLevelWindowMSW::MSWGetSystemMenu() const
 
 bool wxTopLevelWindowMSW::SetTransparent(wxByte alpha)
 {
-    LONG exstyle = GetWindowLong(GetHwnd(), GWL_EXSTYLE);
+    wxMSWWinExStyleUpdater updateExStyle(GetHwnd());
 
     // if setting alpha to fully opaque then turn off the layered style
     if (alpha == 255)
     {
-        SetWindowLong(GetHwnd(), GWL_EXSTYLE, exstyle & ~WS_EX_LAYERED);
+        updateExStyle.TurnOff(WS_EX_LAYERED).Apply();
         Refresh();
         return true;
     }
 
     // Otherwise, set the layered style if needed and set the alpha value
-    if ((exstyle & WS_EX_LAYERED) == 0 )
+    updateExStyle.TurnOn(WS_EX_LAYERED).Apply();
-        SetWindowLong(GetHwnd(), GWL_EXSTYLE, exstyle | WS_EX_LAYERED);
 
     if ( ::SetLayeredWindowAttributes(GetHwnd(), 0, (BYTE)alpha, LWA_ALPHA) )
         return true;

src/msw/treectrl.cpp

@@ -40,6 +40,7 @@
 
 #include "wx/msw/private.h"
 #include "wx/msw/winundef.h"
+#include "wx/msw/private/winstyle.h"
 
 #include "wx/imaglist.h"
 #include "wx/itemattr.h"
@@ -3904,15 +3905,13 @@ void wxTreeCtrl::DoFreeze()
 
     // In addition to disabling redrawing, we also need to disable scrollbar
     // updates that would still happen otherwise.
-    const LONG_PTR styleOld = ::GetWindowLongPtr(GetHwnd(), GWL_STYLE);
+    wxMSWWinStyleUpdater(GetHwnd()).TurnOn(TVS_NOSCROLL);
-    ::SetWindowLongPtr(GetHwnd(), GWL_STYLE, styleOld | TVS_NOSCROLL);
 }
 
 void wxTreeCtrl::DoThaw()
 {
     // Undo temporary TVS_NOSCROLL addition.
-    const LONG_PTR styleOld = ::GetWindowLongPtr(GetHwnd(), GWL_STYLE);
+    wxMSWWinStyleUpdater(GetHwnd()).TurnOff(TVS_NOSCROLL);
-    ::SetWindowLongPtr(GetHwnd(), GWL_STYLE, styleOld & ~TVS_NOSCROLL);
 
     wxTreeCtrlBase::DoThaw();
 }

src/msw/window.cpp

@@ -79,6 +79,7 @@
 
 #include "wx/msw/private.h"
 #include "wx/msw/private/keyboard.h"
+#include "wx/msw/private/winstyle.h"
 #include "wx/msw/dcclient.h"
 #include "wx/msw/seh.h"
 #include "wx/private/textmeasure.h"
@@ -341,12 +342,8 @@ static void EnsureParentHasControlParentStyle(wxWindow *parent)
      */
     while ( parent && !parent->IsTopLevel() )
     {
-        LONG exStyle = wxGetWindowExStyle(parent);
+        // force the parent to have this style
-        if ( !(exStyle & WS_EX_CONTROLPARENT) )
+        wxMSWWinExStyleUpdater(GetHwndOf(parent)).TurnOn(WS_EX_CONTROLPARENT);
-        {
-            // force the parent to have this style
-            wxSetWindowExStyle(parent, exStyle | WS_EX_CONTROLPARENT);
-        }
 
         parent = parent->GetParent();
     }
@@ -1406,11 +1403,8 @@ void wxWindowMSW::MSWUpdateStyle(long flagsOld, long exflagsOld)
         // this function so instead of simply setting the style to the new
         // value we clear the bits which were set in styleOld but are set in
         // the new one and set the ones which were not set before
-        long styleReal = ::GetWindowLong(GetHwnd(), GWL_STYLE);
+        wxMSWWinStyleUpdater updateStyle(GetHwnd());
-        styleReal &= ~styleOld;
+        updateStyle.TurnOff(styleOld).TurnOn(style);
-        styleReal |= style;
-
-        ::SetWindowLong(GetHwnd(), GWL_STYLE, styleReal);
 
         // we need to call SetWindowPos() if any of the styles affecting the
         // frame appearance have changed
@@ -1424,15 +1418,9 @@ void wxWindowMSW::MSWUpdateStyle(long flagsOld, long exflagsOld)
     }
 
     // and the extended style
-    long exstyleReal = wxGetWindowExStyle(this);
+    wxMSWWinExStyleUpdater updateExStyle(GetHwnd());
-
+    if ( updateExStyle.TurnOff(exstyleOld).TurnOn(exstyle).Apply() )
-    if ( exstyle != exstyleOld )
     {
-        exstyleReal &= ~exstyleOld;
-        exstyleReal |= exstyle;
-
-        wxSetWindowExStyle(this, exstyleReal);
-
         // ex style changes don't take effect without calling SetWindowPos
         callSWP = true;
     }
@@ -1443,8 +1431,8 @@ void wxWindowMSW::MSWUpdateStyle(long flagsOld, long exflagsOld)
         // also to make the change to wxSTAY_ON_TOP style take effect: just
         // setting the style simply doesn't work
         if ( !::SetWindowPos(GetHwnd(),
-                             exstyleReal & WS_EX_TOPMOST ? HWND_TOPMOST
+                             updateExStyle.IsOn(WS_EX_TOPMOST) ? HWND_TOPMOST
-                                                         : HWND_NOTOPMOST,
+                                                               : HWND_NOTOPMOST,
                              0, 0, 0, 0,
                              SWP_NOMOVE | SWP_NOSIZE | SWP_NOACTIVATE |
                              SWP_FRAMECHANGED) )
@@ -2434,7 +2422,7 @@ bool wxWindowMSW::MSWProcessMessage(WXMSG* pMsg)
     // must not call IsDialogMessage() then, it would simply hang (see #15458).
     if ( m_hWnd &&
             HasFlag(wxTAB_TRAVERSAL) &&
-                (wxGetWindowExStyle(this) & WS_EX_CONTROLPARENT) )
+                wxHasWindowExStyle(this, WS_EX_CONTROLPARENT) )
     {
         // intercept dialog navigation keys
         MSG *msg = (MSG *)pMsg;
@@ -4470,17 +4458,7 @@ bool wxWindowMSW::IsDoubleBuffered() const
 
 void wxWindowMSW::SetDoubleBuffered(bool on)
 {
-    // Get the current extended style bits
+    wxMSWWinExStyleUpdater(GetHwnd()).TurnOnOrOff(on, WS_EX_COMPOSITED);
-    long exstyle = wxGetWindowExStyle(this);
-
-    // Twiddle the bit as needed
-    if ( on )
-        exstyle |= WS_EX_COMPOSITED;
-    else
-        exstyle &= ~WS_EX_COMPOSITED;
-
-    // put it back
-    wxSetWindowExStyle(this, exstyle);
 }
 
 // ---------------------------------------------------------------------------

src/propgrid/manager.cpp

@@ -1508,10 +1508,8 @@ void wxPropertyGridManager::RecreateControls()
                 #define WS_EX_COMPOSITED        0x02000000L
             #endif
 
-            HWND hWnd = (HWND)m_pToolbar->GetHWND();
+            wxMSWWinExStyleUpdater(GetHwndOf(m_pToolbar))
-
+                .TurnOn(WS_EX_COMPOSITED);
-            ::SetWindowLong( hWnd, GWL_EXSTYLE,
-                             ::GetWindowLong(hWnd, GWL_EXSTYLE) | WS_EX_COMPOSITED );
             */
 
         #endif