学习三层架构，遇到个问题，求助大牛们
学习三层架构，遇到这个问题，代码检查了，应该没有问题，层之间的映射关系也对着，求助：
程序代码：
App.config:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<connectionStrings>
<add name="ConnectionString"
connectionString="Data Source=.\sqlexpress;Initial Catalog=AddressList;Integrated Security=True"
providerName="System.Data.SqlClient"/>
</connectionStrings>
</configuration>
SqlhelperDB.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
namespace SQLDAL
{
///针对SQL Server数据库操作的通用类：
public class SqlDbHelper
{
private static string connString =
ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
public static string ConnectionString
{
get { return connString; }
set { connString = value; }
}
//编写ExecuteDataTable方法，对数据库进行非连接式查询操作：
public static DataTable ExecuteDataTable(string commandText, CommandType commandType, SqlParameter[] parameters)
{
DataTable data = new DataTable();
using (SqlConnection conn = new SqlConnection(connString))
{
using (SqlCommand cmd = new SqlCommand(commandText, conn))
{
= commandType;
if (parameters != null)
{
foreach (SqlParameter param in parameters)
{
cmd.Parameters.Add(param);
}
}
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(data);
}
}
return data;
}
//继续编写俩个重载的ExecuteDataTable方法：
public static DataTable ExecuteDataTable(string commandText)
{
return ExecuteDataTable(commandText, CommandType.Text, null);
}
public static DataTable ExecuteDataTable(string commandText, CommandType commandType)
{
return ExecuteDataTable(commandText, commandType, null);
}
//编写ExecuteReader方法，对数据库进行连接式查询：
public static SqlDataReader ExecuteReader(string commandText, CommandType commandType, SqlParameter[] parameters)
{
SqlConnection conn = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(commandText, conn);
= commandType;
if (parameters != null)
{
foreach (SqlParameter param in parameters)
{
cmd.Parameters.Add(param);
}
}
conn.Open();
return cmd.ExecuteReader(CommandBehavior.CloseConnection);
}
//继续编写俩个重载ExecuteReader方法
public static SqlDataReader ExecuteReader(string commandText)
{
return ExecuteReader(commandText, CommandType.Text, null);
}
public static SqlDataReader ExecuteReader(string commandText, CommandType commandType)
{
return ExecuteReader(commandText, commandType, null);
}
//编写ExecuteScalar方法，对数据库进行单个值的检索
public static Object ExecuteScalar(string commandText, CommandType commandType, SqlParameter[] parameters)
{
object result = null;
using (SqlConnection conn = new SqlConnection(connString))
{
using (SqlCommand cmd = new SqlCommand(commandText, conn))
{
= commandType;
if (parameters != null)
{
foreach (SqlParameter param in parameters)
{
cmd.Parameters.Add(param);
}
}
conn.Open();
result = cmd.ExecuteScalar();
}
}
return result;
}
//继续编写俩个重载ExecuteScalar方法：
public static Object ExecuteScalar(string commandText)
{
return ExecuteScalar(commandText, CommandType.Text, null);
}
public static Object ExecuteScalar(string commandText, CommandType commandType)
{
return ExecuteScalar(commandText, commandType, null);
}
//编写ExecuteNonQuery方法，对数据库进行增、删、改操作：
public static int ExecuteNonQuery(string commandText, CommandType commandType, SqlParameter[] parameters)
{
int count = 0;
using (SqlConnection conn = new SqlConnection(connString))
{
using (SqlCommand cmd = new SqlCommand(commandText, conn))
{
= commandType;
if (parameters != null)
{
foreach (SqlParameter param in parameters)
{
cmd.Parameters.Add(param);
}
}
conn.Open();
count = cmd.ExecuteNonQuery();
}
}
return count;
}
//继续编写俩个重载ExecuteNonQuery方法：
public static int ExecuteNonQuery(string commandTex)
{
return ExecuteNonQuery(commandTex, CommandType.Text, null);
}
public static int ExecuteNonQuery(string commandText, CommandType commandType)
{
return ExecuteNonQuery(commandText, commandType, null);
}
}
}
BLL层：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace BLL
{
public class User
{
SQLDAL.User user = new SQLDAL.User();
public bool Login(string userName, string userPwd)
{
return user.Login(userName,userPwd);
}
public bool Update(Model.User model)
{
return user.Update(model);
}
}
}
SQLDA层：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
namespace SQLDAL
{
//数据访问类：User
public partial class User
{
public User()
{ }
#region Method
//判断用户名、密码是否正确：
public bool Login(string userName, string userPassword)
{
StringBuilder strSql = new StringBuilder();
strSql.Append("select count(1) from [User] ");
strSql.Append(" where UserName=@UserName and Password=@UserPassword");
SqlParameter[] parameters = {
new SqlParameter("@UserName",SqlDbType.NVarChar,50),
new SqlParameter("@UserPassword",SqlDbType.NVarChar,50)
};
parameters[0].Value = userName;
parameters[1].Value = userPassword;
int n = Convert.ToInt32(SqlDbHelper.ExecuteScalar(strSql.ToString(), CommandType.Text, parameters));
if (n == 1)
{
return true;
}
else
{
return false;
}
}
}
哪错了
