Call MSWOnInitDone() when using IFileDialog too

This allows to use the new style dialog for the file dialogs for which
Centre() or SetSize() had been called, as we can now position the window
even when not using a hook function.

As there is no IFileDialogEvents function corresponding to CDN_INITDONE
notification, use the first call to OnTypeChange() instead.

include/wx/msw/filedlg.h

@@ -51,7 +51,7 @@ private:
     // called when the dialog is created
     void MSWOnInitDialogHook(WXHWND hwnd);
 
-    // called from the hook procedure on CDN_INITDONE reception
+    // called when the dialog initialization is fully done
     void MSWOnInitDone(WXHWND hDlg);
 
     // called when the currently selected file changes in the dialog

samples/dialogs/dialogs.cpp

@@ -1741,6 +1741,8 @@ void MyFrame::FilesOpen(wxCommandEvent& WXUNUSED(event) )
                         wxEmptyString, wxEmptyString, wildcards,
                         wxFD_OPEN|wxFD_MULTIPLE);
 
+    dialog.Centre(wxCENTER_ON_SCREEN);
+
     if (dialog.ShowModal() == wxID_OK)
     {
         wxArrayString paths, filenames;

src/msw/filedlg.cpp

@@ -218,7 +218,8 @@ class wxFileDialogMSWData
 public:
     explicit wxFileDialogMSWData(wxFileDialog* fileDialog)
 #if wxUSE_IFILEOPENDIALOG
-        : m_fileDialog(fileDialog)
+        : m_fileDialog(fileDialog),
+          m_typeAlreadyChanged(false)
 #endif // wxUSE_IFILEOPENDIALOG
     {
         m_bMovedWindow = false;
@@ -263,6 +264,24 @@ public:
 
     wxSTDMETHODIMP OnTypeChange(IFileDialog* pfd) wxOVERRIDE
     {
+        // There is no special notification for the dialog initialization, but
+        // this function is always called when it's shown, so use it for
+        // generating this notification as well.
+        if ( !m_typeAlreadyChanged )
+        {
+            m_typeAlreadyChanged = true;
+
+            wxCOMPtr<IOleWindow> window;
+            HRESULT hr = pfd->QueryInterface(wxIID_PPV_ARGS(IOleWindow, &window));
+            if ( SUCCEEDED(hr) )
+            {
+                HWND hwnd;
+                hr = window->GetWindow(&hwnd);
+                if ( SUCCEEDED(hr) )
+                    m_fileDialog->MSWOnInitDone(hwnd);
+            }
+        }
+
         m_fileDialog->MSWOnTypeChange(FileDialogGetFileTypeIndex(pfd));
 
         return S_OK;
@@ -273,6 +292,8 @@ public:
 
     wxFileDialog* const m_fileDialog;
 
+    bool m_typeAlreadyChanged;
+
     DECLARE_IUNKNOWN_METHODS;
 #endif // wxUSE_IFILEOPENDIALOG
 
@@ -582,11 +603,11 @@ int wxFileDialog::ShowModal()
 
     /*
         We need to use the old style dialog in order to use a hook function
-        which allows us to position it or use custom controls in it but, if
-        possible, we prefer to use the new style one instead.
+        which allows us to use custom controls in it but, if possible, we
+        prefer to use the new style one instead.
     */
 #if wxUSE_IFILEOPENDIALOG
-    if ( (!m_data || !m_data->m_bMovedWindow) && !HasExtraControlCreator() )
+    if ( !HasExtraControlCreator() )
     {
         const int rc = ShowIFileDialog(hWndParent);
         if ( rc != wxID_NONE )