dbhelp.cs

一个简单的网上书店

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
namespace  DAL
{
    public class DBHelp
    {
        private static SqlConnection conn;
        private static SqlCommand cmd;
        /// <summary>
        /// 连接数据库
        /// </summary>
        /// <returns>conn</returns>
        public static SqlConnection GetConn
        {
            get
            {
                conn = new SqlConnection(ConfigurationManager.ConnectionStrings["conn"].ConnectionString);
                if (conn == null)
                {
                    conn.Open();
                }
                if (conn.State != ConnectionState.Open)
                {
                    conn.Open();

                }
                return conn;
            }

        }
        /// <summary>
        /// 数据表不带参数的查询
        /// </summary>
        /// <param name="sql"></param>
        /// <returns></returns>
        public static DataTable DataTable(string sql)
        {
            SqlDataAdapter dap = new SqlDataAdapter(sql, GetConn);
            DataTable dt = new DataTable();
            dap.Fill(dt);
            return dt;
        }
        /// <summary>
        /// 数据表带参数的查询
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="para"></param>
        /// <returns></returns>
        public static DataTable Table(string sql, params SqlParameter[] para)
        {
            cmd.Parameters.Clear();
            cmd = new SqlCommand(sql, GetConn);
            cmd.Parameters.AddRange(para);

            SqlDataAdapter dap = new SqlDataAdapter();
            dap.SelectCommand = cmd;
            DataTable dt = new DataTable();
            dap.Fill(dt);
            return dt;

        }
        /// <summary>
        /// 不带参数的查询
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static SqlDataReader Sel(string str)
        {
            cmd = new SqlCommand(str, GetConn);
            SqlDataReader reader = cmd.ExecuteReader();
            return reader;
        }
        /// <summary>
        /// 带参数的查询
        /// </summary>
        /// <param name="str">sql语句</param>
        /// <param name="p1">参数</param>
        /// <returns>sqldatareader</returns>
        public static SqlDataReader Selparam(string str, SqlParameter[] p1)
        {
            cmd = new SqlCommand(str, GetConn);
            cmd.Parameters.AddRange(p1);
            SqlDataReader reader = cmd.ExecuteReader();
            return reader;
        }
        /// <summary>
        /// 不带参数的增删改
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static int Rework(string str)
        {
            cmd = new SqlCommand(str, GetConn);
            int i = cmd.ExecuteNonQuery();
            return i;
        }
        /// <summary>
        /// 带参数的增删改
        /// </summary>
        /// <param name="str"></param>
        /// <param name="p1"></param>
        /// <returns></returns>
        public static int Rework1(string str, SqlParameter[] p1)
        {
            cmd = new SqlCommand(str, GetConn);
            cmd.Parameters.AddRange(p1);          
            int i = cmd.ExecuteNonQuery();
            return i;
        }

    }
}