Windows Vista contains new Win32-Dialogs to save and open a file. There are also the old dialogs from XP available.

Windows Presentation Foundation has two wrapper-classes for Win32-Dialogs. The Microsoft.Win32-Namespace contains a SaveFileDialog- and an OpenFileDialog-class. The classes are located in the PresentationFramework-Assembly, one of the central assemblies of WPF.

When you use the classes from Microsoft.Win32-Namespace, you get the old dialogs from XP. In the snippet below the OpenFileDialog is opened.

Microsoft.Win32.OpenFileDialog dlg =
  new Microsoft.Win32.OpenFileDialog();
dlg.ShowDialog()

With the two lines above the dialog below is shown, and that’s the old-style Windows XP OpenFileDialog:

Windows Forms also wraps the two Dialogs SaveFileDialog and OpenFileDialog with classes in the namespace System.Windows.Forms. Add a reference to the assembly System.Windows.Forms.dll to your WPF-Project, and you can use these wrapper-classes. The interesting part is that they show per default the new Vista Dialog.

System.Windows.Forms.OpenFileDialog dlg =
  new System.Windows.Forms.OpenFileDialog();
dlg.ShowDialog();

With the lines above the new Vista Dialog is displayed:

Both WinForms-Dialog-Classes contain a property called AutoUpgradeEnabled (inherited from FileDialog, property is supported in .NET Versions 3.5, 3.0 SP1 and 2.0 SP1). This property is per default true, so the FileDialog-Instance will automatically upgrade appearance and behavior when running on Windows Vista. Set it to false, to get the old dialog-style:

System.Windows.Forms.OpenFileDialog dlg =
  new System.Windows.Forms.OpenFileDialog();
dlg.AutoUpgradeEnabled = false;
dlg.ShowDialog();

On XP, the AutoUpgradeEnabled-property doesn’t have any effect, of course, there’s only the old dialog available.

Fazit: The cool thing about Microsoft.Win32 is that you can add a using-directive to your WPF-Project and use the classes inside that namespace without a full qualified name. Adding a using-directive for System.Windows.Forms isn’t a good thing in a WPF-Project. There are many double-matches in System.Windows.Forms and e.g. WPF’s System.Windows.Controls-Namespace, like e.g. the Button-class. So the compiler needs full qualified names. But if you wan’t to use the new Dialogs, you have to use the Wrappers from Windows Forms, but don’t add a using-directive for System.Windows.Forms, use full qualified names instead.

There are also other possibilities to get the new vista dialogs. E.g. you could make a Win32-call into comdlg32.dll, but the already available wrappers from Windows Forms are the easiest and fastest way to do it. And you won’t program something, if it’s already there, right? But you have to know that it is there. 8-)

I think Microsoft will update the classes in Microsoft.Win32 in the near future, maybe in the upcoming servicing release for .NET 3.5 planned for Summer 2008? It’s really a little bit strange, WPF is the technology to create first class Vista apps, and its wrappers show still old dialogs, while Windows Forms wrappers don’t…