登录验证用户名和密码-ASP.NET

Question

 public static bool CheckLogin(string userName, string password)
            {
                string sqlConnectionStr = "Server = .; DataBase = Experiment; User ID = sa; Password = 585858";
                SqlConnection sqlConnection = new SqlConnection(sqlConnectionStr);
                sqlConnection.Open();

                string sqlCommandStr = "select * from Administrator where admin_name = '" + userName + "'and admin_psw = '" + password + "'";
                SqlCommand sqlCommand = new SqlCommand(sqlCommandStr, sqlConnection);
                SqlDataReader sqlDataReader = sqlCommand.ExecuteReader();
                if (sqlDataReader.Read())
                {
                    return true;
                }
                else
                {
                    return false;
                }

            }

请问我这样做为什么不能验证用户名和密码？sqlDataReader和sqlCommand之间到底有什么关系啊，我的sqlCommandStr里限定了从用户名为userName并且密码为password（这两个都是通过函数传进来的）选择数据，那么sqlDataReader.ExecuteReader后读到的数据应该也就是这一行啊

Answer 1

自己检查变量名前后是不是有空格了，打印出sqlCommandStr 去数据库执行看是否能选出记录，如果你的密码md5，你传递的值也要md5加密后在对比
sqlCommand用于执行sql语句，还有一个DataAdapter也是用来执行sql语句填充DataTable之类用的，自己找本ado.net基础的书来看
http://blog.csdn.net/jintougao/article/details/8587661

 string sqlCommandStr = "select * from Administrator where admin_name = '" + userName + "'and admin_psw = '" + password + "'";
Response.Write(sqlCommandStr);Response.End();/////