string path=null;

             FolderBrowserDialog fbd = new FolderBrowserDialog();

             fbd.Description = "请选择文件夹";

             if (fbd.ShowDialog()==System.Windows.Forms.DialogResult.OK)

             {

                  path = fbd.SelectedPath;

             }

             foreach(string fileName in System.IO.Directory.GetFiles(path))

             {

                 System.Windows.Forms.MessageBox.Show(fileName);

             }