sqlserver批量更新

写过批量更新的代码，为了方便查找，发上来

class DBHelper
    {
        //操作配置文件
        Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
        //先取一次，做为对比的基础
        SqlConnection conn = new SqlConnection();
        SqlCommand comm = new SqlCommand();
        //链接数据库
        public void Open()
        {
            conn = new SqlConnection(config.AppSettings.Settings["connstr"].Value);
            conn.Open();
        }
        //断开连接
        public void Close()
        {
            conn.Close();
        }
        //执行sql，并返回第一行第一列
        public object ExecuteScalar(string sql)
        {
            comm.CommandText = sql;
            comm.Connection = conn;
            return comm.ExecuteScalar();
        }
        //执行sql，并返回执行结果
        public DataTable GetResult(string sql)
        {
            SqlDataAdapter sda = new SqlDataAdapter(sql, conn);
            DataTable dt = new DataTable();
            sda.Fill(dt);
            return dt;
        }
        //执行sql
        public void ExecuteNonQuery(string sql)
        {
            comm.CommandText = sql;
            comm.ExecuteNonQuery();
        }
        //批量更新
        public void Update(DataTable dt, string tablename)
        {
            using (SqlBulkCopy sqlcopy = new SqlBulkCopy(conn))
            {
                sqlcopy.BulkCopyTimeout = 10000;
                sqlcopy.DestinationTableName = tablename;
                sqlcopy.WriteToServer(dt);
            }
        }
    }