var ss = Server.MapPath(""); //C:\Users\Administrator\Desktop\Csharp测试程序\TestMVC\TestMVC

            ss = ss + "/bin/index.html";

            using (StreamReader sr = new StreamReader(ss, System.Text.Encoding.GetEncoding("gb2312"))) //以gb2312编码方式读取

            {

                string htmlContent = sr.ReadToEnd();

                return Content(htmlContent);

            }
 //StreamReader sr = new StreamReader(path,Encoding.Default) //Encoding.Default 该编码方式没有gb2312