.net MVC 连接数据本地数据库三种方法

     <appSettings>
       <add key="webpages:Version" value="2.0.0.0" />
       <add key="webpages:Enabled" value="false" />
       <add key="PreserveLoginUrl" value="true" />
       <add key="ClientValidationEnabled" value="true" />
       <add key="UnobtrusiveJavaScriptEnabled" value="true" />
       <add key="con" value="server=.\sqlexpress; user id = sa;password = a123456;database = xsgl1;max pool size=512;"/>
     </appSettings>
     <connectionStrings>
      <add name="conSql" connectionString="server=(local)\sqlexpress; User Id = sa;password = a123456;database = xsgl1;max pool size=512;"/>
    </connectionStrings> 

Configuration

      public class HomeController : Controller
       {
           //
           // GET: /Home/

           public ActionResult Index()
           {
               #region connect sql function one
               SqlConnectionStringBuilder one = new SqlConnectionStringBuilder();
              one.DataSource = "(local)\\sqlexpress";
              one.InitialCatalog = "xsgl1";
              one.UserID = "sa";
              one.Password = "a123456";
              one.MaxPoolSize = ;
              SqlConnection sct = new SqlConnection(one.ConnectionString);
              #endregion
              #region connect sql function two
              //string conn = ConfigurationManager.AppSettings["con"].ToString();
              //SqlConnection sct = new SqlConnection(conn);
              #endregion
              #region connect sql function three
              //string conn = ConfigurationManager.ConnectionStrings["conSql"].ConnectionString;
              //SqlConnection sct = new SqlConnection(conn);
              #endregion
              SqlCommand scm = new SqlCommand();
              scm.Connection = sct;
              scm.CommandType = CommandType.Text;
              scm.CommandText = "select 课程名 from kc where 课程号='A001'";
              sct.Open();
              SqlDataReader sdr = scm.ExecuteReader();
              if (sdr.Read())
              {
                  ViewBag.hao = sdr["课程名"];
              }
              sdr.Close();
              return View();
          }
          public ActionResult About()
          {
              return View();
          }
      }

Controller

  @{
      ViewBag.Title = "Index";
  }
  @ViewBag.hao
  <h2>Index</h2>

View