//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");
          }
       }
    }
}