//winform   ShowMsg封装了MessageBox.show()方法

public void MySqlLogin(string auccount,string pwd)

{
　　 string conn = ConfigurationManager.ConnectionStrings["MConn"].ConnectionString;
    string sql = "select*from `User` where uName=@uname and uPwd=@upwd";

    MySqlParameter[]spar =

    {

       new MySqlParameter("@uname",auccount),

       new MySqlParameter("@upwd",pwd)

    };

    using (MySqlConnection connection = new MySqlConnection(conn))

    {

       connection.Open();

       using (MySqlCommand mcommd=new MySqlCommand(sql,connection))

       {

          mcommd.Parameters.AddRange(spar);

          if (mcommd.ExecuteReader().HasRows)

          {

            ShowMsg("Success!");

          }

          else

          {

            ShowMsg("No Account");

          }

       }

    }
}