sqlHelper

using System;
using System.Text;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;
using System.Collections;
namespace GJ
{
    using System.Configuration;
    using System.Data;//DatSet..Table SqlDataAdapter
    using System.Data.SqlClient;//SqlConnection Command DataReader
    
        public class SqlHelper
        {
            //连接字符串
            //1、添加引用 2、导入命名空间 为了使用ConfigurationManager
            private static string conStr = Properties.Resources.DBConnection;

            //增删改查
            //查找数据  ExecuteScalar()返回首行首列   ExecuteReader()  DataTable


            /// <summary>
            /// 返回DataTable
            /// </summary>
            /// <param name="sql">所用的sql语句</param>
            /// <param name="param">可变，可以传参也可以不传参数</param>
            /// <returns></returns>
            public static DataTable ExecuteDataTable(string sql, params SqlParameter[] param)
            {
                DataTable dt = new DataTable();
                using (SqlConnection con = new SqlConnection(conStr))
                {
                    using (SqlDataAdapter adapter = new SqlDataAdapter(sql, con))
                    {
                        //添加参数
                        adapter.SelectCommand.Parameters.AddRange(param);
                        //1.打开链接，如果连接没有打开，则它给你打开；如果打开，就算了
                        //2.去执行sql语句，读取数据库
                        //3.sqlDataReader,把读取到的数据填充到内存表中
                        adapter.Fill(dt);
                    }
                }
                return dt;
            }
            /// <summary>
            /// 向数据库提交修改的数据
            /// </summary>
            /// <param name="dt"></param>
            /// <returns></returns>
            public static int ExecuteUpdate(string sql,DataTable dt)
            {
                int lines=0;
                using (SqlConnection con = new SqlConnection(conStr))
                {
                    using (SqlDataAdapter adapter = new SqlDataAdapter(sql,con))
                    {
                        using (SqlCommandBuilder cb = new SqlCommandBuilder(adapter))
                        {
                            lines=adapter.Update(dt);
                        }
                        
                    }
                }
                return lines;
            }

            /// <summary>
            /// 执行查询，返回首行首列
            /// </summary>
            /// <param name="sql"></param>
            /// <param name="param"></param>
            /// <returns></returns>
            public static object ExecuteScalar(string sql, params SqlParameter[] param)
            {
                object o = null;
                using (SqlConnection con = new SqlConnection(conStr))
                {
                    using (SqlCommand cmd = new SqlCommand(sql, con))
                    {
                        cmd.Parameters.AddRange(param);
                        con.Open();

                        o = cmd.ExecuteScalar();
                    }
                }
                return o;
            }


            /// <summary>
            /// 执行查询，返回SqlDataReader对象
            /// </summary>
            /// <param name="sql"></param>
            /// <param name="param"></param>
            /// <returns></returns>
            public static SqlDataReader ExecuteReader(string sql, params SqlParameter[] param)
            {
                SqlDataReader reader = null;
                using (SqlConnection con = new SqlConnection(conStr))
                {
                    using (SqlCommand cmd = new SqlCommand(sql, con))
                    {
                        cmd.Parameters.AddRange(param);
                        con.Open();

                        reader = cmd.ExecuteReader();
                    }
                }
                return reader;
            }

            /// <summary>
            /// 执行增删改，返回受影响的行数
            /// </summary>
            /// <param name="sql"></param>
            /// <param name="param"></param>
            /// <returns></returns>
            public static int ExecuteNonQuery(string sql, params SqlParameter[] param)
            {
                int n = -1;
                using (SqlConnection con = new SqlConnection(conStr))
                {
                    using (SqlCommand cmd = new SqlCommand(sql, con))
                    {
                        cmd.Parameters.AddRange(param);
                        con.Open();
                        n = cmd.ExecuteNonQuery();
                    }
                }
                return n;
            }

        }
    
}