Folder dialog

OpenFolderDialog from the Meziantou.Framework.Win32.Dialogs package shows the folder picker of Windows, the same dialog as File Explorer uses to open files, configured to select a folder. It needs no UI framework: it works from a console application as well as from WPF or Windows Forms.

dotnet package add Meziantou.Framework.Win32.Dialogs

The examples of this page show a dialog: they are compiled, not run, by the build of the repository.

Select a folder

var dialog = new OpenFolderDialog();
var result = dialog.ShowDialog();
if (result == DialogResult.OK)
{
    Console.WriteLine($"Selected folder: {dialog.SelectedPath}");
}

ShowDialog blocks until the user closes the dialog. SelectedPath is the full path of the folder when the result is DialogResult.OK, and null otherwise: each call resets it.

Configure the dialog

var dialog = new OpenFolderDialog
{
    Title = "Select a folder",
    OkButtonLabel = "Choose",
    InitialDirectory = @"C:\Users",
    ChangeCurrentDirectory = false,
};

var result = dialog.ShowDialog();
if (result == DialogResult.OK)
{
    Console.WriteLine($"Selected folder: {dialog.SelectedPath}");
}

InitialDirectory accepts a path, with \ or / separators, or a shell location such as shell:Downloads. When the folder does not exist, or names a drive that is not mounted, the dialog ignores it and opens the folder Windows would choose by default:

var dialog = new OpenFolderDialog
{
    // A path or a shell location. The dialog ignores a location that does not exist.
    InitialDirectory = "shell:Downloads",
};

dialog.ShowDialog();

Set the owner window

A dialog with an owner window stays in front of it, and the owner is disabled while the dialog is open. Pass the handle of the window to ShowDialog. In the code of a WPF Window:

var dialog = new OpenFolderDialog
{
    Title = "Sample Open Folder dialog",
    OkButtonLabel = "Select Folder",
};

var hwnd = new System.Windows.Interop.WindowInteropHelper(this).Handle;
var result = dialog.ShowDialog(hwnd);

In Windows Forms, pass the Handle of the form. Without an owner, ShowDialog() uses the active window of the calling thread.

In the code of a WPF Window, DialogResult refers to the Window.DialogResult property: write Meziantou.Framework.Win32.DialogResult.OK to compare the result of ShowDialog.

Handle errors

ShowDialog returns DialogResult.Cancel when the user closes the dialog, and DialogResult.Abort when the dialog cannot be shown. It does not throw: LastHResult gives the error code of the last call, which Marshal.GetExceptionForHR turns into an exception:

var dialog = new OpenFolderDialog();
switch (dialog.ShowDialog())
{
    case DialogResult.OK:
        Console.WriteLine($"Selected folder: {dialog.SelectedPath}");
        break;

    case DialogResult.Cancel:
        // The user closed the dialog
        break;

    default:
        // The dialog could not be shown: LastHResult tells why
        throw Marshal.GetExceptionForHR(dialog.LastHResult) ?? new InvalidOperationException("The dialog failed");
}