File Open Dialog with Encodings combobox under Vista

Question

I currently use the TOpenTextFileDialog as it has the Encodings option, but under Vista it appears using the older open dialog style. I'd like the new style open dialog, but with an encoding combobox that I can fill with custom strings. Basically I want the exact open dialog that Notepad shows under Vista. Of course I also need the corresponding save dialog as well.

I've done some research and it seems that the OFN_ENABLETEMPLATE flag causes the Vista common dialog to fall back to the old style. Unfortunately that's also the flag that lets the TOpenTextFileDialog modify the window to add the encodings combobox (if I understand things properly.)

Does anyone have a suggestion on how to get what I want under Vista but still have it work under XP? I assume that Windows 7 will have the same issue. I'm using D2009. Thanks for any suggestions or help!

Answer 1

With Vista a new way of dealing with file dialogs has been introduced, for more information google for the IFileDialog interface or have a look at this blog post. As you say yourself, using the OFN_ENABLETEMPLATE flag causes the Vista common dialog to fall back to the old style.

With Delphi 2007 and 2009 you can use the TFileOpenDialog and TFileSaveDialog in the Vista Dialogs components category. To make your application compatible with pre-Vista Windows versions you should keep using the TOpenTextFileDialog for those, and check at runtime whether you are on Vista and can use the new dialogs:

if Win32MajorVersion >= 6 then begin
  // use TFileOpenDialog
  // ...
end else begin
  // use TOpenTextFileDialog
  // ...
end;

Now you only need to add the customization to the Vista dialog. The blog post shows how to do this, by adding a handler for OnExecute of the dialog (because at the time when this is called the IFileDialog interface has been set up already), querying the Dialog member of the file dialog for the IFileDialogCustomize interface, and using this to add the additional controls.