winform选择文件夹

using System; using System.Windows.Forms;  namespace WindowsFormsApp1 {     public partial class Form1 : Form     {         public Form1()         {             InitializeComponent();         }          /// <summary>         /// 好用一点的打开目录         /// </summary>         /// <param name="sender"></param>         /// <param name="e"></param>         private void button1_Click(object sender, EventArgs e)         {             SaveFileDialog sfd = new SaveFileDialog();             sfd.DefaultExt = "xls";             sfd.FileName = "默认名字";             sfd.Filter = "Excel Document(*.xls)|*.xls";             //如果设置了默认路径，那下次打开依然是这个默认路径，             //不应该和RestoreDirectory =true同时使用。             //sfd.InitialDirectory = "C:\";             //保存路径，每次打开，都选择上次的目录，             sfd.RestoreDirectory = true;              if (sfd.ShowDialog() != System.Windows.Forms.DialogResult.OK)             {                 return;             }         }          /// <summary>         /// 难用的打开目录         /// </summary>         /// <param name="sender"></param>         /// <param name="e"></param>         private void button2_Click(object sender, EventArgs e)         {             FolderBrowserDialog fbd = new FolderBrowserDialog();             //即使设置了这个默认路径，但滚动条不会自动滚动到那儿             fbd.SelectedPath = "D:\app";             if(fbd.ShowDialog()!=DialogResult.OK)             {                 return;             }         }     } }