System.Windows.Forms.SaveFileDialog saveFile = new System.Windows.Forms.SaveFileDialog();
            saveFile.Title = "新建文件";
            saveFile.FileName = "";
            saveFile.Filter = "*.txt";        //新建文件类型为txt
            
            string filename = string.Empty;
            if (saveFile.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                // Save document
                System.IO.FileStream fs = (System.IO.FileStream)saveFile.OpenFile();//输出文件
               
            }
            else
            {
                return;
            }

System.Windows.Forms.OpenFileDialog openFile = new System.Windows.Forms.OpenFileDialog();
            openFile.Title = "打开文件";
            openFile.Filter = _filePathParameter.fileFilter();
            if (openFile.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                TextValue = openFile.FileName;         //获取文件位置+文件名
            }