Use SelectedPath Property of the FolderBrowserDialog Class

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Introduction

This article is not of interest to advanced programmers, as it answers the following questions:

• How to use SelectedPath property of FolderBrowserDialog class?
• How to open a FolderBrowserDialog at the selected logical drive?

But...

Background

Despite the fact that the MSDN provides a clear definition of RootFolder and SelectedPath properties, it cited the examples do not provide a clear view.

I'll try to fill this gap.

Using the Code

Run an application and fill comboBox1 the next items:

private void Form1_Load(object sender, EventArgs e)
        {
            //The first 'comboBox1' item is string a "Browse..."
            comboBox1.Items.Add("Browse...");

            /*Returns an array of string 
             * containing the names of the logical drives on the current computer.*/
            foreach (var Drives in Environment.GetLogicalDrives())
            {
                DriveInfo DriveInf = new DriveInfo(Drives);
                /*IsReady indicates whether a drive is ready. 
                 * For example, it indicates whether a CD is in a CD drive 
                 * or whether a removable storage device is ready for read/write operations. 
                 * If you do not test whether a drive is ready, 
                 * and it is not ready, querying the drive using DriveInfo 
                 * will raise an IOException.(MSDN)*/
                if (DriveInf.IsReady == true)
                {
                    //Populate 'comboBox1' with logical drives
                    comboBox1.Items.Add(DriveInf.Name);
                }
            }
        }

If you want to explore how to work a SelectedPath property dynamically - add any subfolder to the comboBox1.

For this:

• Select an item (any drive) comboBox1 control.
• This is will open FolderBrowserDialog at the item.
• In the FolderBrowserDialog, select any subfolder from the tree file system and click <OK>.
  The path of selected subfolder is added to collection items comboBox1.
• Select new item.

As result is opened and deployed, the FolderBrowserDialog with the RootFolder and any subfolders
that are beneath it will appear in the dialog box and be selectable.

NOTE:

The SelectedPath is an absolute path that is a subfolder of RootFolder.

 private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            //'comboBox1' selected item
            string item = comboBox1.SelectedItem.ToString();

            //Create new class FolderBrowserDialog
            FolderBrowserDialog fbd = new FolderBrowserDialog();

            //Call method 'OpenFolderBrowserDialog'
            OpenFolderBrowserDialog(fbd, item);
        }
private void OpenFolderBrowserDialog(FolderBrowserDialog folderBrowserDialog, string item)
        {
            /*Only the specified folder and any subfolders 
            * that are beneath it will appear in the dialog box and be selectable. 
            * The SelectedPath property, along with RootFolder, 
            * determines what the selected folder will be when the dialog box is displayed, 
            * as long as SelectedPath is an absolute path that is a subfolder of RootFolder 
            * (or more accurately, points to a subfolder of the shell 
            * namespace represented by RootFolder).(MSDN)*/

            //Gets the path to the system special folder 
            //that is identified by the specified enumeration.(MSDN)*/
            folderBrowserDialog.RootFolder = Environment.SpecialFolder.Desktop;

            /*If the SelectedPath property is set before showing the dialog box, 
             * the folder with this path will be the selected folder,
             * as long as SelectedPath is set to an absolute path 
             * that is a subfolder of RootFolder 
             * (or more accurately, points to a subfolder of the shell 
             * namespace represented by RootFolder).(MSDN)*/
            //In case 
            folderBrowserDialog.SelectedPath = item;

            //If not necessary to crate new folder than...
            folderBrowserDialog.ShowNewFolderButton = false;

            try
            {
                DialogResult dr = folderBrowserDialog.ShowDialog();

                //Open 'FolderBrowserDialog'
                if (dr == DialogResult.OK)
                {
                    /* To see how it works 'SelectedPath' property
                     * add any subfolder to the 'comboBox1' 
                     * and choose it again*/
                    comboBox1.Items.Add(folderBrowserDialog.SelectedPath);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

On the other hand:

If "Browse..." has been selected in comboBox1 control, I see no reason to suppose that someone there is a folder with the same name, SelectedPath does not work and as a result, FolderBrowserDialog will be opened with the RootFolder=Environment.SpecialFolder.Desktop only!

We see that "...as long as SelectedPath is set to an absolute path that is a subfolder of RootFolder (or more accurately, points to a subfolder of the shell namespace represented by RootFolder)". (MSDN)

History

• March 23, 2016: Article published