SqlHelper和数据访问层

using System;
using System.Collections.Generic;
using System.Text;
using System.Configuration;
using System.Data.SqlClient;
using System.Data;
using System.Collections;

namespace Common
{
    /// <summary>
    /// SqlHelper类提供很高的数据访问性能, 
    /// 使用SqlClient类的通用定义.
    /// </summary>
    public abstract class SqlHelper
    {
        //定义数据库连接串
        public static readonly string CONN_STRING =
            ConfigurationManager.ConnectionStrings["ConnString"].ConnectionString;
  
        public static readonly string CONN = "server=.;uid=sa;pwd=sa;database=MyOffice";
        // 存贮Cache缓存的Hashtable集合
        private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());

        /// <summary>
        /// 使用连接字符串，执行一个SqlCommand命令（没有记录返回）
        /// 使用提供的参数集.
        /// </summary>
        /// <param name="connectionString">一个有效的SqlConnection连接串</param>
        /// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param>
        /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
        /// <param name="commandParameters">执行命令的参数集</param>
        /// <returns>受此命令影响的行数</returns>
        public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {

            SqlCommand cmd = new SqlCommand();

            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);

                int val = cmd.ExecuteNonQuery();

                cmd.Parameters.Clear();

                return val;
            }
        }

        /// <summary>
        /// 在一个存在的连接上执行数据库的命令操作
        /// 使用提供的参数集.
        /// </summary>
        /// <param name="conn">一个存在的数据库连接对象</param>
        /// <param name="commandType">命令类型CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
        /// <param name="commandParameters">执行命令的参数集</param>
        /// <returns>受此命令影响的行数</returns>
        public static int ExecuteNonQuery(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {

            SqlCommand cmd = new SqlCommand();

            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);

            int val = cmd.ExecuteNonQuery();

            cmd.Parameters.Clear();

            return val;

        }


        /// <summary>
        /// 在一个事务的连接上执行数据库的命令操作
        /// 使用提供的参数集.
        /// </summary>
        /// <param name="trans">一个存在的事务</param>
        /// <param name="commandType">命令类型CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
        /// <param name="commandParameters">执行命令的参数集</param>
        /// <returns>受此命令影响的行数</returns>
        public static int ExecuteNonQuery(SqlTransaction trans, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);

            int val = cmd.ExecuteNonQuery();

            cmd.Parameters.Clear();

            return val;
        }

        /// <summary>
        /// 在一个连接串上执行一个命令，返回一个SqlDataReader对象
        /// 使用提供的参数.
        /// </summary>
        /// <param name="connectionString">一个有效的SqlConnection连接串</param>
        /// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param>
        /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
        /// <param name="commandParameters">执行命令的参数集</param>
        /// <returns>一个结果集对象SqlDataReader</returns>
        public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();

            SqlConnection conn = new SqlConnection(connectionString);


            // 如果不存在要查询的对象，则发生异常
            // 连接要关闭
            // CommandBehavior.CloseConnection在异常时不发生作用
            try
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);

                SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

                cmd.Parameters.Clear();

                return rdr;
            }
            catch
            {
                conn.Close();
                throw;
            }
        }



        /// <summary>
        /// 在一个连接串上执行一个命令，返回表中第一行，第一列的值
        /// 使用提供的参数.
        /// </summary>
        /// <param name="connectionString">一个有效的SqlConnection连接串</param>
        /// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param>
        /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
        /// <param name="commandParameters">执行命令的参数集</param>        
        /// <returns>返回的对象，在使用时记得类型转换</returns>
        public static  object  ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();

            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);

                object  val = cmd.ExecuteScalar();

                cmd.Parameters.Clear();

                return val;
            }
        }



        /// <summary>
        /// 在一个连接上执行一个命令，返回表中第一行，第一列的值
        /// 使用提供的参数.
        /// </summary>
        /// <param name="connectionString">一个有效的SqlConnection连接</param>
        /// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param>
        /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
        /// <param name="commandParameters">执行命令的参数集</param>        
        /// <returns>返回的对象，在使用时记得类型转换</returns>
        public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();

            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);

            object val = cmd.ExecuteScalar();

            cmd.Parameters.Clear();

            return val;
        }

        /// <summary>
        /// 在一个连接串上执行一个命令，返回数据集
        /// 使用提供的参数.
        /// </summary>
        /// <param name="connectionString">一个有效的SqlConnection连接串</param>
        /// <param name="cmdType">命令类型CommandType(stored procedure, text, etc.)</param>
        /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param>
        /// <param name="commandParameters">执行命令的参数集</param>
        /// <returns>返回数据集</returns>
        public static DataSet ExecuteDataSet(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {

            SqlCommand cmd = new SqlCommand();

            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                PrepareCommand(cmd, conn, null, commandType, commandText, commandParameters);

                SqlDataAdapter adapter = new SqlDataAdapter(cmd);
                DataSet ds = new DataSet();
                adapter.Fill(ds);

                cmd.Parameters.Clear();
                return ds;
            }
        }

        /// <summary>
        /// 在缓存中添加参数数组
        /// </summary>
        /// <param name="cacheKey">参数的Key</param>
        /// <param name="cmdParms">参数数组</param>
        public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters)
        {
            parmCache = commandParameters;
        }



        /// <summary>
        /// 提取缓存的参数数组
        /// </summary>
        /// <param name="cacheKey">查找缓存的key</param>
        /// <returns>返回被缓存的参数数组</returns>
        public static SqlParameter[] GetCachedParameters(string cacheKey)
        {
            SqlParameter[] cachedParms = (SqlParameter[])parmCache;

            if (cachedParms == null)
                return null;

            SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length];

            for (int i = 0, j = cachedParms.Length; i < j; i++)
                clonedParms = (SqlParameter)((ICloneable)cachedParms).Clone();

            return clonedParms;
        }



        /// <summary>
        /// 提供一个SqlCommand对象的设置
        /// </summary>
        /// <param name="cmd">SqlCommand对象</param>
        /// <param name="conn">SqlConnection 对象</param>
        /// <param name="trans">SqlTransaction 对象</param>
        /// <param name="cmdType">CommandType 如存贮过程，T-SQL</param>
        /// <param name="cmdText">存贮过程名或查询串</param>
        /// <param name="cmdParms">命令中用到的参数集</param>
        private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();

            cmd.Connection = conn;
            cmd.CommandText = cmdText;

            if (trans != null)
                cmd.Transaction = trans;

            cmd.CommandType = cmdType;

            if (cmdParms != null)
            {
                foreach (SqlParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }
    }
}

----访问----
using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using Common;
using team1.Model;

namespace team1.SQLServerDAL
{


    /// <summary>
    /// 员工信息表的数据访问操作
    /// </summary>
    public partial class UserInfoService
    {


        /// <summary>
        /// 获得所有员工信息表
        /// </summary>
        /// <returns>员工信息表集合</returns>
        public IList<UserInfo> GetAllUserInfos2()
        {
            //string sql = "SELECT UserId,UserName,Password,DepartId,Gender,UserStateId " +
            //    "FROM UserInfo";

            IList<UserInfo> allUserInfos = new List<UserInfo>();

            using (SqlDataReader rdr = SqlHelper.ExecuteReader(
                SqlHelper.CONN_STRING, CommandType.StoredProcedure, ""))
            {
                while (rdr.Read())
                {
                    UserInfo userInfo = new UserInfo();
                    userInfo.UserId = (string)rdr["UserId"];
                    userInfo.UserName = (string)rdr["UserName"];
                    userInfo.Password = (string)rdr["Password"];
                    userInfo.DepartId = (int)rdr["DepartId"];
                    userInfo.Gender = (int)rdr["Gender"];
                    userInfo.UserStateId = (int)rdr["UserStateId"];
                    userInfo.UserStateName = (string)rdr["UserStateName"];
                    userInfo.DepartName = (string)rdr["DepartName"];
                    userInfo.RoleName = (string)rdr["RoleName"];

                    allUserInfos.Add(userInfo);
                }
            }

            return allUserInfos;
        }


        #region 验证用户登陆信息

        public UserInfo CheckLogin(string loginID, string loginPwd)
        {
            SqlParameter[] pas = new SqlParameter[]
{
new SqlParameter("@userId",SqlDbType.VarChar,50),
new SqlParameter("@password",SqlDbType.VarChar,50)
};

            pas[0].Value = loginID;
            pas[1].Value = loginPwd;

            using (SqlDataReader rdr = SqlHelper.ExecuteReader(
                SqlHelper.CONN_STRING, CommandType.StoredProcedure, "", pas))
            {
                if (rdr.Read())
                {
                    UserInfo userInfo = new UserInfo();
                    userInfo.UserId = (string)rdr["UserId"];
                    userInfo.UserName = (string)rdr["UserName"];
                    userInfo.Password = (string)rdr["Password"];
                    userInfo.DepartId = (int)rdr["DepartId"];
                    userInfo.Gender = (int)rdr["Gender"];
                    userInfo.UserStateId = (int)rdr["UserStateId"];
                    userInfo.DepartName = (string)rdr["DepartName"];
                    userInfo.RoleName = (string)rdr["RoleName"];
                    userInfo.RoleId = (int)rdr["RoleId"];
                    return userInfo;
                }
            }
            return null;
        }

        /// <summary>
        /// 判断用户名称是否存在
        /// </summary>
        /// <param name="loginID">用户登陆ID</param>
        /// <returns></returns>
        public bool CheckLoginByLoginId(string loginID)
        {
            string sql = "Select * from  userInfo where UserId='" + loginID + "'";
            using (SqlDataReader rdr = SqlHelper.ExecuteReader(
              SqlHelper.CONN_STRING, CommandType.Text, sql))
            {
                if (rdr.Read())
                {
                    return true;
                }
                return false;
            }
        }

        //根据用户名称获得密码
        public string CheckLoginByLoginPwd(string loginID)
        {
            string sql = "Select password from  userInfo where UserId='" + loginID + "'";
            return (string)SqlHelper.ExecuteScalar(SqlHelper.CONN_STRING, CommandType.Text, sql);
        }
        #endregion

        /// <summary>
        /// 根据输入用户名前缀返回相关用户名
        /// </summary>
        /// <param name="foreName">用户输入姓名前缀</param>
        /// <param name="count">数量</param>
        /// <returns></returns>
        public IList<string> GetUsersByPreName(string foreName, int count)
        {
            IList<string> user = new List<string>();

            string sql = "select top " + count + " * from UserInfo where UserName like '" + foreName.Trim() + "%'";

            using (SqlDataReader rdr = SqlHelper.ExecuteReader(SqlHelper.CONN_STRING, CommandType.Text, sql, null))
            {
                int i = 0;
                while (rdr.Read())
                {

                    UserInfo userInfo = new UserInfo();

                    userInfo.UserId = (string)rdr["UserId"];
                    userInfo.UserName = (string)rdr["UserName"];

                    try
                    {
                        user.Add(userInfo.UserName);
                    }
                    catch (Exception ex)
                    {
                        Console.WriteLine(ex.Message);
                    }


                }
            }
            return user;
        }

        /// <summary>
        /// 点击搜索范围时根据条件进行查询所有用户姓名
        /// </summary>
        /// <param name="branchId">机构ID</param>
        /// <param name="departId">部门ID</param>
        /// <param name="loginId">工号</param>
        /// <param name="userName">用户姓名</param>
        /// <returns></returns>
        public IList<UserInfo> GetUserInfoSearch(int branchId, int departId, string loginId, string userName)
        {
            string sql = "select u.userName,u.userId from userInfo u join departInfo " +
            "d on(u.departId=d.departId) where 1=1";
            if (branchId != 0)
            {
                sql += " and d.branchId=" + branchId;
            }
            if (departId != 0)
            {
                sql += " and u.departId =" + departId;
            }
            if (userName != null && !userName.Trim().Equals(""))
            {
                sql += " and u.userName = '" + userName + "'";
            }

            if (loginId != null && !"".Equals(loginId.Trim()))
            {
                sql += " and u.loginId='" + loginId + "'";
            }

            if (branchId == 0 && departId == 0 && loginId.Trim() == "" && userName.Trim() == "")
            {
                return null;
            }

            IList<UserInfo> allUserInfos = new List<UserInfo>();

            using (SqlDataReader rdr = SqlHelper.ExecuteReader(
                SqlHelper.CONN_STRING, CommandType.Text, sql))
            {
                while (rdr.Read())
                {
                    UserInfo userInfo = new UserInfo();
                    userInfo.UserId = (string)rdr["UserId"];
                    userInfo.UserName = (string)rdr["UserName"];
                    allUserInfos.Add(userInfo);
                }

                return allUserInfos;
            }
        }


        public IList<UserInfo> GetUserInfoByDepartId(int departId)
        {
            string sql = "SELECT UserId,UserName,Password,DepartId,Gender,UserStateId FROM UserInfo where departId = " + departId;

            IList<UserInfo> userInfoList = new List<UserInfo>();

            using (SqlDataReader rdr = SqlHelper.ExecuteReader(
                SqlHelper.CONN_STRING, CommandType.Text, sql))
            {
                while (rdr.Read())
                {
                    UserInfo userInfo = new UserInfo();
                    userInfo.UserId = (string)rdr["UserId"];
                    userInfo.UserName = (string)rdr["UserName"];
                    userInfo.Password = (string)rdr["Password"];
                    userInfo.DepartId = (int)rdr["DepartId"];
                    userInfo.Gender = (int)rdr["Gender"];
                    userInfo.UserStateId = (int)rdr["UserStateId"];
                    userInfoList.Add(userInfo);
                }
            }

            return userInfoList;

        }

        /// <summary>
        /// 根据ID查询员工信息表2
        /// </summary>
        /// <param name="userId">员工信息表ID</param>
        /// <returns>员工信息表对象</returns>
        public UserInfo GetUserInfoByUserId2(string userId)
        {
            SqlParameter para = new SqlParameter("@UserId", SqlDbType.VarChar, 30);
            para.Value = userId;
            using (SqlDataReader rdr = SqlHelper.ExecuteReader(
                SqlHelper.CONN_STRING, CommandType.StoredProcedure, "", para))
            {
                if (rdr.Read())
                {
                    UserInfo userInfo = new UserInfo();
                    userInfo.UserId = (string)rdr["UserId"];
                    userInfo.UserName = (string)rdr["UserName"];
                    userInfo.Password = (string)rdr["Password"];
                    userInfo.DepartId = (int)rdr["DepartId"];
                    userInfo.Gender = (int)rdr["Gender"];
                    userInfo.UserStateId = (int)rdr["UserStateId"];

                    userInfo.UserStateName = (string)rdr["UserStateName"];
                    userInfo.DepartName = (string)rdr["DepartName"];
                    userInfo.RoleName = (string)rdr["RoleName"];

                    return userInfo;
                }
            }

            return null;
        }

        /// <summary>
        ///  根据部门编号查询用户
        /// </summary>
        /// <param name="departId"></param>
        /// <returns></returns>
        public UserInfo GetUserByDepartId(int DepartId)
        {
            string sql = "SELECT UserId,UserName,Password,DepartId,Gender,UserStateId " +
            "FROM UserInfo where departId = @DepartId";

            SqlParameter pa = new SqlParameter("@DepartId", SqlDbType.Int, 4);
            pa.Value = DepartId;

            using (SqlDataReader rdr = SqlHelper.ExecuteReader(
                SqlHelper.CONN_STRING, CommandType.Text, sql, pa))
            {
                while (rdr.Read())
                {
                    UserInfo userInfo = new UserInfo();
                    userInfo.UserId = (string)rdr["UserId"];
                    userInfo.UserName = (string)rdr["UserName"];
                    userInfo.Password = (string)rdr["Password"];
                    userInfo.DepartId = (int)rdr["DepartId"];
                    userInfo.Gender = (int)rdr["Gender"];
                    userInfo.UserStateId = (int)rdr["UserStateId"];
                    return userInfo;
                }
            }

            return null;

        }
    }
}