<span style="font-family: Arial, Helvetica, sans-serif;">#region 读取TXT 文件，放到Label中</span>

        private void ReadTXT(Label lab) {

            string strTxtAll = "";//定义一个string变量

            string abc = "C:\Users\xxb\Desktop\1.txt";//路径

            FileStream fs = new FileStream(abc, FileMode.Open, FileAccess.Read, FileShare.None);

            StreamReader sr = new StreamReader(fs, Encoding.GetEncoding("GB2312"));

            string line = sr.ReadLine();

            strTxtAll = line + "\r\n";

            for (int ac = 0; line != null; ac++) {

                line = sr.ReadLine();

                strTxtAll += line + "\r\n";

            }

            lab.Text = strTxtAll;

            sr.Close();

            fs.Close();

        }

        #endregion

调用即可：

  ReadTxt(label1);