SqlParameter 参数化查询，参数无法替换，求助，谢谢。

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.Sql;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.Common;

using System.Windows.Forms;

namespace WMS
{
    class Access
    {

      public static  string connStr = ConfigurationManager.ConnectionStrings["ConStr"].ConnectionString;

      public static string dataDir = AppDomain.CurrentDomain.BaseDirectory;

        public static void dataDirDeclare()
        {
            if ( dataDir.EndsWith(@"\bin\debug\")|| dataDir.EndsWith(@"\bin\release\"))
            {
                dataDir = System.IO.Directory.GetParent(dataDir).Parent.Parent.FullName;
                AppDomain.CurrentDomain.SetData("DataDirectory",dataDir);
            }
        }
        public Access()
        {
             dataDirDeclare();
        }

        public string getName(string userid)
        {
            using (SqlConnection conn = new SqlConnection(connStr))
            {
                conn.Open();
                using (SqlCommand comm = conn.CreateCommand())
                {
                    comm.CommandText = @"select username  from userinfo where userid = @name ";
                    comm.Parameters.Add(new SqlParameter ("name",userid));
                  return  Convert.ToString( comm.ExecuteScalar());
                }
            }

        }
        public  bool login(string name, string password)
        {

            bool flag = false;

            using (SqlConnection conn = new SqlConnection(connStr))
            {
                conn.Open();
                using (SqlCommand comm = conn.CreateCommand())
                {
                    comm.CommandText = @"select count(*)  from userinfo where userid = @name and password = @password";
                    comm.Parameters.Add(new SqlParameter ("name",name));
                    comm.Parameters.Add(new SqlParameter ("password",password));

                    int i = Convert.ToInt32(comm.ExecuteScalar());
                    if (i == 0)
                    {
                        flag = false;

                    }
                    else
                    {
                        flag = true;
                    }

                }

            }
            return flag;
        }

        public bool  querySql(string sql,params string[] s )
        {
            bool flag = false;
            using (SqlConnection conn = new SqlConnection(connStr))
            {
                conn.Open();
                using (SqlCommand comm = conn.CreateCommand())
                {

                    comm.CommandText = @"select userid,password from userinfo where userid = @userid and password = @password ";
                    comm.Parameters.Add(new SqlParameter("userid", "wj"));
                    comm.Parameters.Add(new SqlParameter("password", "111111"));

                   string userid = (string) comm.ExecuteScalar();


                }
             }
            return flag;

        }
    }
}
------------------------
这个类里面函数getName（），login() 在调用时都参数@都可以替换，但是函数querySql（）在调用时参数死活都不替换，
请求帮忙解决，谢谢，非常感谢 --------------------编程问答-------------------- public bool  querySql(string sql,params string[] s )
        {
            bool flag = false;
            using (SqlConnection conn = new SqlConnection(connStr))
            {
                conn.Open();
                using (SqlCommand comm = conn.CreateCommand())
                {

                    comm.CommandText = @"select userid,password from userinfo where userid = @userid and password = @password ";
                    comm.Parameters.Add(new SqlParameter("userid", "wj"));
                    comm.Parameters.Add(new SqlParameter("password", "111111"));

                   string userid = (string) comm.ExecuteScalar();


                }
             }
            return flag;

        } 就是这个函数。请帮忙分析分析 --------------------编程问答-------------------- 参数使用有很多方法的..甚至你用linq 连参数都省了.

系统报什么错? --------------------编程问答-------------------- ExecuteScalar 只能返回单行，单列的值。

select userid~~,password~~ from userinfo where userid = @userid and password = @password --------------------编程问答-------------------- 系统没报错，所以很奇怪，但是上面的两个函数都没问题，我就不知道为上面了 --------------------编程问答-------------------- comm.CommandText = @"select [userid],[password] from [userinfo] where [userid] = @userid and [password]= @password ";
comm.Parameters.AddWithValue("@userid", "wj");
comm.Parameters.AddWithValue("@password", "111111");
--------------------编程问答-------------------- 非常感谢， --------------------编程问答--------------------

引用 5 楼 net_lover 的回复:

comm.CommandText = @"select [userid],[password] from [userinfo] where [userid] = @userid and [password]= @password ";
comm.Parameters.AddWithValue("@userid", "wj");
comm.Parameters.AddWithValue("@p……

字段加"[]"，好习惯啊 --------------------编程问答--------------------

引用 5 楼 net_lover 的回复:

comm.CommandText = @"select [userid],[password] from [userinfo] where [userid] = @userid and [password]= @password ";
comm.Parameters.AddWithValue("@userid", "wj");
comm.Parameters.AddWithValue("@pa……

oyeah 就是没有写@
--------------------编程问答-------------------- 学习一下

补充：.NET技术 ,  C#