Folder Browser Dialog in C#: Pick, Show in a TextBox, Multi-Select

Nobody enjoys typing a long folder path. In a C# Windows Forms app, the folder browser dialog fixes that: create a FolderBrowserDialog, call ShowDialog(), and read SelectedPath when it returns DialogResult.OK.

In this tutorial, I’ll put together a Report Exporter for a small Seattle accounting firm and use the folder browser dialog in C# three ways: pick one folder, show the chosen path in a TextBox, and select several folders at once.

You’ll run everything on .NET 10 under C:\DotNetDemo\FolderDialogDemo, which holds four client folders: Austin, Boston, Denver and Seattle.

What the Finished Folder Browser Dialog Tool Looks Like

Here’s where you’ll end up. You browse for a destination folder, add client folders with a multi-select dialog, and click Export reports to write one summary file per client.

There’s no .csproj. If file-based apps are new to you, my guide to creating a console application in Visual Studio Code covers the setup.

Step 1: Show a FolderBrowserDialog and Read SelectedPath

Start with the smallest working program. The three #:property lines turn a plain .cs file into a WinForms app on .NET 10.

#:property TargetFramework=net10.0-windows
#:property UseWindowsForms=true
#:property PublishAot=false

class Program
{
    [STAThread]
    static void Main()
    {
        ApplicationConfiguration.Initialize();
        using var dialog = new FolderBrowserDialog
        {
            Description = "Choose a client folder",
            UseDescriptionForTitle = true,
            InitialDirectory = @"C:\DotNetDemo\FolderDialogDemo\Clients",
            ShowPinnedPlaces = false
        };

        DialogResult result = dialog.ShowDialog();
        Console.WriteLine($"Result: {result}");
        Console.WriteLine($"SelectedPath: {dialog.SelectedPath}");
    }
}

Output:

Result: OK
SelectedPath: C:\DotNetDemo\FolderDialogDemo\Clients\Seattle

You need PublishAot=false because file-based apps turn on Native AOT by default. Without it, I got build error NETSDK1175: Windows Forms isn’t supported with trimming.

Windows Forms expects a single-threaded apartment, and top-level statements run on an MTA thread. That’s why the dialog lives in a Main method marked [STAThread].

Checkpoint: Seattle was selected when Select Folder was pressed, so the output shows Result: OK and the full path. DialogResult is an enum, so you compare it like any other enum in C#.

Cancel returns DialogResult.Cancel, so check the result first. The using declaration disposes the dialog, as explained in Dispose and Finalize in C#.

Step 2: Show the Folder Browser Dialog Path in a TextBox

Now the real tool. Here’s the complete ReportExporter.cs; you’ll walk through its three button handlers in this step and the next two:

#:property TargetFramework=net10.0-windows
#:property UseWindowsForms=true
#:property PublishAot=false

class Program
{
    [STAThread]
    static void Main()
    {
        ApplicationConfiguration.Initialize();
        Application.Run(new ExportForm());
    }
}

class ExportForm : Form
{
    const string DemoRoot = @"C:\DotNetDemo\FolderDialogDemo";
    readonly TextBox txtDestination = new() { Left = 20, Top = 40, Width = 360 };
    readonly Button btnBrowse = new() { Text = "Browse...", Left = 390, Top = 36, Width = 120, Height = 34 };
    readonly ListBox lstClients = new() { Left = 20, Top = 110, Width = 360, Height = 90 };
    readonly Button btnAddClients = new() { Text = "Add clients...", Left = 390, Top = 108, Width = 120, Height = 34 };
    readonly Button btnExport = new() { Text = "Export reports", Left = 20, Top = 215, Width = 150, Height = 34 };
    readonly Label lblStatus = new() { Left = 20, Top = 262, Width = 490, Height = 80 };

    public ExportForm()
    {
        Text = "Report Exporter";
        ClientSize = new Size(530, 350);
        Controls.Add(new Label { Text = "Save reports to:", Left = 20, Top = 18, AutoSize = true });
        Controls.Add(new Label { Text = "Client folders to export:", Left = 20, Top = 88, AutoSize = true });
        Controls.AddRange([txtDestination, btnBrowse, lstClients, btnAddClients, btnExport, lblStatus]);
        btnBrowse.Click += BrowseDestination;
        btnAddClients.Click += AddClientFolders;
        btnExport.Click += ExportReports;
    }

    void BrowseDestination(object? sender, EventArgs e)
    {
        using var dialog = new FolderBrowserDialog
        {
            Description = "Choose where to save the reports",
            UseDescriptionForTitle = true,
            InitialDirectory = Directory.Exists(txtDestination.Text) ? txtDestination.Text : DemoRoot,
            ShowNewFolderButton = true,
            ShowPinnedPlaces = false
        };
        if (dialog.ShowDialog(this) == DialogResult.OK)
            txtDestination.Text = dialog.SelectedPath;
    }

    void AddClientFolders(object? sender, EventArgs e)
    {
        using var dialog = new FolderBrowserDialog
        {
            Description = "Select one or more client folders",
            UseDescriptionForTitle = true,
            InitialDirectory = Path.Combine(DemoRoot, "Clients"),
            Multiselect = true,
            ShowNewFolderButton = false,
            ShowPinnedPlaces = false
        };
        if (dialog.ShowDialog(this) != DialogResult.OK) return;
        foreach (string path in dialog.SelectedPaths)
            if (!lstClients.Items.Contains(path)) lstClients.Items.Add(path);
    }

    void ExportReports(object? sender, EventArgs e)
    {
        if (!Directory.Exists(txtDestination.Text) || lstClients.Items.Count == 0)
        {
            lblStatus.Text = "Pick a destination folder and at least one client folder.";
            return;
        }
        var lines = new List<string>();
        foreach (string folder in lstClients.Items)
        {
            string client = Path.GetFileName(folder);
            string[] invoices = Directory.GetFiles(folder, "*.csv");
            string report = Path.Combine(txtDestination.Text, $"{client}-report.txt");
            File.WriteAllLines(report, [$"Client: {client}", $"Invoices: {invoices.Length}", .. invoices.Select(f => Path.GetFileName(f))]);
            lines.Add($"{client}: {invoices.Length} invoices -> {Path.GetFileName(report)}");
        }
        lblStatus.Text = $"Exported {lines.Count} reports:\n" + string.Join("\n", lines);
    }
}

BrowseDestination opens the dialog and copies SelectedPath into txtDestination. It’s wired up with btnBrowse.Click += BrowseDestination;, a normal WinForms event in C#.

Checkpoint: the TextBox holds the Exports path. Click Browse… again and the dialog reopens there, because InitialDirectory reads the TextBox.

The TextBox stays editable, so your users can paste a path too. If a typed folder may not exist yet, create the folder if it does not exist before exporting.

Step 3: Select Multiple Folders with Multiselect and SelectedPaths

Since .NET 9, FolderBrowserDialog supports multi-select. AddClientFolders sets Multiselect = true and reads every folder from SelectedPaths.

Checkpoint: the Folder box shows "Boston" "Seattle". You hold Ctrl while clicking to pick several, and the foreach loop adds each new path to the ListBox.

SelectedPath still holds just one path in multi-select mode. In my run it was Boston, so always loop over SelectedPaths.

On .NET Framework or .NET 8, these properties don’t exist. The old workaround, an OpenFileDialog that maps picked files back to folders, is clumsy; .NET 9 or later is cleaner.

Step 4: Export the Reports to the Folder from the Dialog

ExportReports checks both inputs, then writes one <City>-report.txt per client. The status text comes from a List<string>.

To confirm the export really happened, you can read the files back with a tiny console program:

string exports = @"C:\DotNetDemo\FolderDialogDemo\Exports";
foreach (string report in Directory.GetFiles(exports, "*-report.txt").Order())
{
    Console.WriteLine($"--- {Path.GetFileName(report)}");
    foreach (string line in File.ReadLines(report))
        Console.WriteLine(line);
}

Output:

--- Boston-report.txt
Client: Boston
Invoices: 2
INV-BOS-001.csv
INV-BOS-002.csv
--- Seattle-report.txt
Client: Seattle
Invoices: 3
INV-SEA-001.csv
INV-SEA-002.csv
INV-SEA-003.csv

Checkpoint: both reports are in Exports with real file counts. Rerunning overwrites them; to clear old ones first, see how to delete files from a folder in C#.

How Do I Set the Default Folder in a FolderBrowserDialog?

Use InitialDirectory (added in .NET 6) for the folder the dialog opens in. SelectedPath can preselect a folder too, and it’s your only option on older versions.

SelectedPath starts as an empty string, as the defaults run below shows, so read it only after an OK result. If your tool later cleans up, here’s how to delete a folder in C#.

FolderBrowserDialog Properties and Their Defaults

This program creates a dialog without showing it and prints each default value:

#:property TargetFramework=net10.0-windows
#:property UseWindowsForms=true
#:property PublishAot=false

using var dialog = new FolderBrowserDialog();
Console.WriteLine($"SelectedPath:           \"{dialog.SelectedPath}\"");
Console.WriteLine($"InitialDirectory:       \"{dialog.InitialDirectory}\"");
Console.WriteLine($"RootFolder:             {dialog.RootFolder}");
Console.WriteLine($"ShowNewFolderButton:    {dialog.ShowNewFolderButton}");
Console.WriteLine($"Multiselect:            {dialog.Multiselect}");
Console.WriteLine($"AddToRecent:            {dialog.AddToRecent}");
Console.WriteLine($"ShowHiddenFiles:        {dialog.ShowHiddenFiles}");
Console.WriteLine($"ShowPinnedPlaces:       {dialog.ShowPinnedPlaces}");

Output:

SelectedPath:           ""
InitialDirectory:       ""
RootFolder:             Desktop
ShowNewFolderButton:    True
Multiselect:            False
AddToRecent:            True
ShowHiddenFiles:        False
ShowPinnedPlaces:       True

Property	What it does	Since
UseDescriptionForTitle	Shows Description as the title	.NET Core 3.0
InitialDirectory	Folder the dialog opens in	.NET 6
AddToRecent, ShowHiddenFiles	Recent list entry, hidden folders	.NET 7
OkRequiresInteraction	OK stays disabled until the user navigates	.NET 7
ShowPinnedPlaces	Default items in the navigation pane	.NET 7
Multiselect, SelectedPaths	Pick several folders	.NET 9

I set ShowPinnedPlaces = false so the left pane doesn’t list anyone’s pinned folders. For more window tweaks, see how to hide the minimize, maximize and close buttons.

Which Folder Browser Dialog Setup Should You Use?

One folder: Step 1 plus a TextBox on a form. Several folders: .NET 9 or later with SelectedPaths.

Ready to grow the Report Exporter? These four posts cover the next features I would add:

• Email the exported reports as attachments
• Handle locked or missing files with try-catch

Frequently Asked Questions