diff --git a/include/wx/msw/filedlg.h b/include/wx/msw/filedlg.h
index 86952b6c6b..d2ba87a54f 100644
--- a/include/wx/msw/filedlg.h
+++ b/include/wx/msw/filedlg.h
@@ -34,22 +34,9 @@ public:
     virtual void GetPaths(wxArrayString& paths) const wxOVERRIDE;
     virtual void GetFilenames(wxArrayString& files) const wxOVERRIDE;
     virtual bool SupportsExtraControl() const wxOVERRIDE { return true; }
-    void MSWOnInitDialogHook(WXHWND hwnd);
 
     virtual int ShowModal() wxOVERRIDE;
 
-    // wxMSW-specific implementation from now on
-    // -----------------------------------------
-
-    // called from the hook procedure on CDN_INITDONE reception
-    virtual void MSWOnInitDone(WXHWND hDlg);
-
-    // called from the hook procedure on CDN_SELCHANGE.
-    void MSWOnSelChange(WXHWND hDlg);
-
-    // called from the hook procedure on CDN_TYPECHANGE.
-    void MSWOnTypeChange(WXHWND hDlg, int nFilterIndex);
-
 protected:
 
     virtual void DoMoveWindow(int x, int y, int width, int height) wxOVERRIDE;
@@ -58,6 +45,21 @@ protected:
     virtual void DoGetPosition( int *x, int *y ) const wxOVERRIDE;
 
 private:
+    // Allow it to call MSWOnXXX() functions below.
+    friend class wxFileDialogMSWData;
+
+    // called when the dialog is created
+    void MSWOnInitDialogHook(WXHWND hwnd);
+
+    // called from the hook procedure on CDN_INITDONE reception
+    void MSWOnInitDone(WXHWND hDlg);
+
+    // called from the hook procedure on CDN_SELCHANGE.
+    void MSWOnSelChange(WXHWND hDlg);
+
+    // called from the hook procedure on CDN_TYPECHANGE.
+    void MSWOnTypeChange(WXHWND hDlg, int nFilterIndex);
+
     // The real implementation of ShowModal() using traditional common dialog
     // functions.
     int ShowCommFileDialog(WXHWND owner);
@@ -66,7 +68,7 @@ private:
     int ShowIFileDialog(WXHWND owner);
 
     // Get the data object, allocating it if necessary.
-    struct wxFileDialogMSWData& MSWData();
+    wxFileDialogMSWData& MSWData();
 
 
     wxArrayString m_fileNames;
diff --git a/src/msw/filedlg.cpp b/src/msw/filedlg.cpp
index d6e69363a1..28715b139d 100644
--- a/src/msw/filedlg.cpp
+++ b/src/msw/filedlg.cpp
@@ -149,14 +149,20 @@ void RestoreExceptionPolicy()
 // wxFileDialogMSWData: private data used by the dialog
 // ----------------------------------------------------------------------------
 
-struct wxFileDialogMSWData
+class wxFileDialogMSWData
 {
+public:
     wxFileDialogMSWData()
     {
         m_bMovedWindow = false;
         m_centreDir = 0;
     }
 
+    // Hook function used by the common dialogs: it's a member of this class
+    // just to allow it to call the private functions of wxFileDialog.
+    static UINT_PTR APIENTRY
+    HookFunction(HWND hDlg, UINT iMsg, WPARAM wParam, LPARAM lParam);
+
     // remember if our SetPosition() or Centre() (which requires special
     // treatment) was called
     bool m_bMovedWindow;
@@ -168,10 +174,10 @@ struct wxFileDialogMSWData
 // ----------------------------------------------------------------------------
 
 UINT_PTR APIENTRY
-wxFileDialogHookFunction(HWND      hDlg,
-                         UINT      iMsg,
-                         WPARAM    WXUNUSED(wParam),
-                         LPARAM    lParam)
+wxFileDialogMSWData::HookFunction(HWND      hDlg,
+                                  UINT      iMsg,
+                                  WPARAM    WXUNUSED(wParam),
+                                  LPARAM    lParam)
 {
     switch ( iMsg )
     {
@@ -590,7 +596,7 @@ int wxFileDialog::ShowCommFileDialog(WXHWND hWndParent)
     of.lpstrInitialDir   = dir.c_str();
 
     of.Flags             = msw_flags;
-    of.lpfnHook          = wxFileDialogHookFunction;
+    of.lpfnHook          = wxFileDialogMSWData::HookFunction;
     of.lCustData         = (LPARAM)this;
 
     wxArrayString wildDescriptions, wildFilters;