//1.打开资源管理器

OpenFileDialog open = new OpenFileDialog();

  if (open.ShowDialog() == DialogResult.OK)            

{              

   textBox1.Text =open.FileName;       

 }

//传入txt文件路径参数 读取txt文件所有内容 返回DATATABLE

 public DataTable GetTxt(string pths)
        {
            StreamReader sr = new StreamReader(pths, Encoding.GetEncoding("GB2312"));
            string txt = sr.ReadToEnd().Replace("\r\n", "-");
            string[] nodes = txt.Split(‘-‘);
            DataTable dt = new DataTable();
            dt.Columns.Add("ID", typeof(string));
            foreach (string node in nodes)
            {
                string[] strs = node.Split(‘-‘);
                DataRow dr = dt.NewRow();
                dr["ID"] = strs[0];
                dt.Rows.Add(dr);
            }
            return dt;
        }

C#读取txt文件返回DATATABLE