private void btnOpen_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.InitialDirectory = @"C:\Users\LWP1398\Desktop"; //設(shè)置初始路徑
            ofd.Filter = "Excel文件(*.xls)|*.xls|Csv文件(*.csv)|*.csv|所有文件(*.*)|*.*"; //設(shè)置“另存為文件類型”或“文件類型”框中出現(xiàn)的選擇內(nèi)容
            ofd.FilterIndex = 2; //設(shè)置默認(rèn)顯示文件類型為Csv文件(*.csv)|*.csv
            ofd.Title = "打開文件"; //獲取或設(shè)置文件對(duì)話框標(biāo)題
            ofd.RestoreDirectory = true;
            if (ofd.ShowDialog() == DialogResult.OK)
            {
                //FileName：所選文件的全路徑  SafeFileName：所選的文件名
                txtPath.Text = "FileName:" + ofd.FileName + "\r\n" + "SafeFileName:" + ofd.SafeFileName;
            }
        }

private void button3_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.InitialDirectory = @"C:\Users\LWP1398\Desktop"; //設(shè)置初始路徑
            ofd.Filter = "Excel文件(*.xls)|*.xls|Csv文件(*.csv)|*.csv|所有文件(*.*)|*.*"; //設(shè)置“另存為文件類型”或“文件類型”框中出現(xiàn)的選擇內(nèi)容
            ofd.FilterIndex = 2; //設(shè)置默認(rèn)顯示文件類型為Csv文件(*.csv)|*.csv
            ofd.Title = "打開文件"; //獲取或設(shè)置文件對(duì)話框標(biāo)題
            ofd.RestoreDirectory = true;設(shè)置對(duì)話框是否記憶上次打開的目錄
 
            ofd.Multiselect = true;//設(shè)置多選
            if (ofd.ShowDialog() == DialogResult.OK)
            {
                for (int i = 0; i < ofd.FileNames.Length; i++)
                {
                    txtPath.Text += ofd.FileNames[i] + "\r\n";//輸出一個(gè)路徑回車換行
                }
                for (int i = 0; i < ofd.FileNames.Length; i++)
                {
                    txtPath.Text += ofd.SafeFileNames[i] + "\r\n";
                }
            }
        }

private void button2_Click(object sender, EventArgs e)
        {
            SaveFileDialog sfd=new SaveFileDialog();
            sfd.Filter = "文本文件(*.txt)|*.txt|所有文件|*.*";//設(shè)置文件類型
            sfd.FileName = "保存";//設(shè)置默認(rèn)文件名
            sfd.DefaultExt = "txt";//設(shè)置默認(rèn)格式（可以不設(shè)）
            sfd.AddExtension = true;//設(shè)置自動(dòng)在文件名中添加擴(kuò)展名
            if (sfd.ShowDialog()==DialogResult.OK)
            {
                txtPath.Text = "FileName:" + sfd.FileName + "\r\n" ;
                using (StreamWriter sw = new StreamWriter(sfd.FileName))
                {              
                    sw.WriteLineAsync("今天是個(gè)好天氣");
                }
            }
            MessageBox.Show("ok");
        }

private void saveFileDialog1_FileOk(object sender, CancelEventArgs e)
{
     saveFileDialog1.AddExtension = true; //自動(dòng)添加擴(kuò)展名
     e.Cancel = true; //取消保存操作            
     string 擴(kuò)展名 = System.IO.Path.GetExtension(saveFileDialog1.FileName);
     //判斷擴(kuò)展名并實(shí)現(xiàn)自定義的保存操作(導(dǎo)出)
     if (擴(kuò)展名 == "txt")
     { }
     if (擴(kuò)展名 == "xml")
     { }
}

string defaultPath = "";
FolderBrowserDialog dialog = new FolderBrowserDialog();
//打開的文件夾瀏覽對(duì)話框上的描述
dialog.Description = "請(qǐng)選擇一個(gè)文件夾";
//是否顯示對(duì)話框左下角 新建文件夾 按鈕，默認(rèn)為 true
dialog.ShowNewFolderButton = false;
//首次defaultPath為空，按FolderBrowserDialog默認(rèn)設(shè)置（即桌面）選擇
if (defaultPath != "")
{
	//設(shè)置此次默認(rèn)目錄為上一次選中目錄
	dialog.SelectedPath = defaultPath;
}
//按下確定選擇的按鈕
if (dialog.ShowDialog() == DialogResult.OK)
{
	//記錄選中的目錄
	defaultPath = dialog.SelectedPath;
}
MessageBox.show(defaultPath);