SqlParameter 参数化查询，参数无法替换，求助，谢谢。

Question

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

Answer 1

 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

Answer 2

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?

Answer 3

ExecuteScalar 只能返回单行，单列的值。select userid,password from userinfo where userid = @userid and password = @password

Answer 4

comm.CommandText = @"select [userid],[password] from [userinfo] where [userid] = @userid and [password]= @password ";
comm.Parameters.AddWithValue("@userid", "wj");
comm.Parameters.AddWithValue("@password", "111111");