Open directory dialog

You can use the built-in FolderBrowserDialog class for this. Don't mind that it's in the System.Windows.Forms namespace.

using (var dialog = new System.Windows.Forms.FolderBrowserDialog()){    System.Windows.Forms.DialogResult result = dialog.ShowDialog();}

If you want the window to be modal over some WPF window, see the question How to use a FolderBrowserDialog from a WPF application.

EDIT: If you want something a bit more fancy than the plain, ugly Windows Forms FolderBrowserDialog, there are some alternatives that allow you to use the Vista dialog instead:

• Third-party libraries, such as Ookii dialogs (.NET 4.5+)

• The Windows API Code Pack-Shell:

    using Microsoft.WindowsAPICodePack.Dialogs;  ...  var dialog = new CommonOpenFileDialog();  dialog.IsFolderPicker = true;  CommonFileDialogResult result = dialog.ShowDialog();

  Note that this dialog is not available on operating systems older than Windows Vista, so be sure to check CommonFileDialog.IsPlatformSupported first.

I created a UserControl which is used like this:

  <UtilitiesWPF:FolderEntry Text="{Binding Path=LogFolder}" Description="Folder for log files"/>

The xaml source looks like this:

<UserControl x:Class="Utilities.WPF.FolderEntry"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">    <DockPanel>        <Button Margin="0" Padding="0" DockPanel.Dock="Right" Width="Auto" Click="BrowseFolder">...</Button>        <TextBox Height="Auto" HorizontalAlignment="Stretch" DockPanel.Dock="Right"            Text="{Binding Text, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}" />    </DockPanel></UserControl>

and the code-behind

public partial class FolderEntry {    public static DependencyProperty TextProperty = DependencyProperty.Register("Text", typeof(string), typeof(FolderEntry), new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));    public static DependencyProperty DescriptionProperty = DependencyProperty.Register("Description", typeof(string), typeof(FolderEntry), new PropertyMetadata(null));    public string Text { get { return GetValue(TextProperty) as string; } set { SetValue(TextProperty, value); }}    public string Description { get { return GetValue(DescriptionProperty) as string; } set { SetValue(DescriptionProperty, value); } }    public FolderEntry() { InitializeComponent(); }    private void BrowseFolder(object sender, RoutedEventArgs e) {        using (FolderBrowserDialog dlg = new FolderBrowserDialog()) {            dlg.Description = Description;            dlg.SelectedPath = Text;            dlg.ShowNewFolderButton = true;            DialogResult result = dlg.ShowDialog();            if (result == System.Windows.Forms.DialogResult.OK) {                Text = dlg.SelectedPath;                BindingExpression be = GetBindingExpression(TextProperty);                if (be != null)                    be.UpdateSource();            }        }    } }

Ookii folder dialog can be found at Nuget.

PM> Install-Package Ookii.Dialogs.Wpf

And, example code is as below.

var dialog = new Ookii.Dialogs.Wpf.VistaFolderBrowserDialog();if (dialog.ShowDialog(this).GetValueOrDefault()){    textBoxFolderPath.Text = dialog.SelectedPath;}

More information on how to use it: https://github.com/augustoproiete/ookii-dialogs-wpf