在WPF中调用另存为对话框

                Microsoft.Win32.SaveFileDialog dlg = new Microsoft.Win32.SaveFileDialog();
                dlg.FileName = "User.txt"; // Default file name
                dlg.DefaultExt = ".txt"; // Default file extension
                dlg.Filter = "Text documents (.txt)|*.txt"; // Filter files by extension

                var dir = System.IO.Path.GetDirectoryName(this.txtPlace.Text);
                dlg.InitialDirectory = dir;

                // Show save file dialog box
                Nullable<bool> result = dlg.ShowDialog();

                // Process save file dialog box results
                if (result == true)
                {
                    // Save document
                    this.txtPlace.Text = dlg.FileName;
                }

 Using Save As Dialog in WPF