这是一个操作数据库  查询登录用户名和密码是否正确的方法，把查出的数据存到User类里面，
public User GetUser(string id, string loginPwd)
        {
         
                string sql = string.Format("select id,loginPwd from Users where id={0} and loginPwd='{1}'", id, loginPwd);
                SqlCommand command = new SqlCommand(sql, DBHelper.connection);
                DBHelper.connection.Open();
                SqlDataReader dataReader = command.ExecuteReader();
                if (!dataReader.HasRows)
                {
                    MessageBox.Show("用户名或密码输入不正确", "提示");
                }
                else
                {
                    

                    while (dataReader.Read())
                   1.     user.Id = (int)dataReader["id"];
                   2.     user.LoginPwd = dataReader["LoginPwd"].ToString();

                    dataReader.Close();
                    MessageBox.Show("用户登录成功","提示");
                  
                    MainForm mf = new MainForm();
                    mf.Show();
                    this.Visible = false;//隐藏当前窗体
                    
                }

         
                DBHelper.connection.Close();
              
           

            return user;
        }

1.  和 2.  不管怎么换位置都是第二句报错


哪个大哥给看看怎么个意思  为什么报这个错误呢？应该怎么改啊