WPF (3.5 / Visual Studio 2008) does not ship with an Open File Dialog component like in Windows Forms. You can however still use the Windows Form’s (Win32) open file dialog class to accomplish exactly the same thing with a few lines of code.
1: Microsoft.Win32.OpenFileDialog ofd = new Microsoft.Win32.OpenFileDialog();
2: ofd.Filter = "XML Files (*.XML)|*.xml";
5: txtFilePath.Text = ofd.FileName;