C USES the FolderBrowserDialog class to implement the select open folder method

1. You can use the FolderBrowserDialog class in C# to select folders and record the path to the selected folders.

(1). First, the namespace System.Windows.Forms is introduced;
(2). Then add the [STAThread] attribute to the main entry point of the application, which is the static void Main() method;

/// <summary>
        ///  The application's main entry point. 
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }

(3). Then define our event trigger;

private void button1_Click(object sender, EventArgs e)
        {
            FolderBrowserDialog dilog = new FolderBrowserDialog();
            dilog.Description = " Please select folder ";
            if(dilog.ShowDialog() == DialogResult.OK || dilog.ShowDialog() == DialogResult.Yes)
            {
                path=dilog.SelectedPath;
            }
        }

(4). Open the folder we just selected;

private void button2_Click(object sender, EventArgs e)
        {
            if (!string.IsNullOrEmpty(path))
            {
                System.Diagnostics.Process.Start("Explorer.exe", path);
            }
            else
            {
                MessageBox.Show(" Please select the path ");
            }
        }

So that's it. Select folder.

2. It should be noted that you need to add the [STAThread] property at the entry point of the program. Of course, you can not add this property, but you need to open another thread for processing. The code is as follows:

private void button1_Click(object sender, EventArgs e)
        {
            Thread newThread = new Thread(new ThreadStart(TEST));
            newThread.SetApartmentState(ApartmentState.STA);
            newThread.Start();
            // or 
            //Thread app = new Thread(new ParameterizedThreadStart(TEST));// two TEST Method is not 1 Like, the delegate type is not 1 sample 
            //app.ApartmentState = ApartmentState.STA;
            //app.Start();
        }
        private void TEST(object obj)
        {
            FolderBrowserDialog dilog = new FolderBrowserDialog();
            dilog.Description = " Please select folder ";
            if(dilog.ShowDialog() == DialogResult.OK)
            {
                path=dilog.SelectedPath;
            }
        }
        private void TEST()
        {
            FolderBrowserDialog dilog = new FolderBrowserDialog();
            dilog.Description = " Please select folder ";
            if (dilog.ShowDialog() == DialogResult.OK)
            {
                path = dilog.SelectedPath;
            }
        }