winform 获取文件夹

private void cmd_Open_Click(object sender, System.EventArgs e)
{
    Bool fileOpened = true;
    FolderBrowserDialog folderBrowserDialog1 = new FolderBrowserDialog();
    DialogResult result = folderBrowserDialog1.ShowDialog();
    if( result == DialogResult.OK )
    {
       folderName = folderBrowserDialog1.SelectedPath;
       if(!fileOpened)
       {
         // No file is opened, bring up openFileDialog in selected path.
         openFileDialog1.InitialDirectory = folderName;
         openFileDialog1.FileName = null;
       } 
    }
    txt_Path.Text =folderBrowserDialog1.SelectedPath;
}