由Dapper QueryMultiple 返回数据的问题得出==》Dapper QueryMultiple并不会帮我们识别多个返回值的顺序

异常汇总:http://www.cnblogs.com/dunitian/p/4523006.html#dapper

今天帮群友整理Dapper基础教程的时候手脚快了点,然后遇到了一个小问题,Dapper QueryMultiple 返回数据的问题

多个返回值用QueryMultiple ,这个大家都知道,如果不清楚的看下下面的文档:

这个是官方文档:

Multiple Results

Dapper allows you to process multiple result grids in a single query.

Example:

var sql = 
@"
select * from Customers where CustomerId = @id
select * from Orders where CustomerId = @id
select * from Returns where CustomerId = @id";

using (var multi = connection.QueryMultiple(sql, new {id=selectedId}))
{
   var customer = multi.Read<Customer>().Single();
   var orders = multi.Read<Order>().ToList();
   var returns = multi.Read<Return>().ToList();
   ...
} 

按照文档来,为啥没数据呢,就ID有值?难道多表只能传一个参数,而且必须有关系???NONONO,如果这么多限制还叫Dapper吗??

给你3s找错误。。。。。

 

其实就是顺序弄颠倒了,园友可以当个经验==》Dapper QueryMultiple并不会帮我们识别多个返回值的顺序

Read获取的时候必须是按照上面返回表的顺序 (article,qqmodel,seotkd)

var articleList = multi.Read<Temp>();//类不见得一定得和表名相同
var QQModelList = multi.Read<QQModel>();
var SeoTKDList = multi.Read<SeoTKD>();

 

官方文档是这样写的,那我们能不能玩点其他的?就一定得定义一个类来获取对应的强类型吗?多返回值就不能动态获取吗???NONONO

直接

if (!multi.IsConsumed)
{

  var articleList = multi.Read();
  var QQModelList = multi.Read();
  var SeoTKDList = multi.Read();

}

一样的效果

周日会有一篇文章详细说下Dapper的,现在得出省了。。。。立刻,马上。。。

 

附录:

            using (SqlConnection conn = new SqlConnection(connStr))
            {
                string sqlStr = @"select Id,Title,Author from Article where Id = @Id 
                                  select * from QQModel where Name = @Name 
                                  select * from SeoTKD where Status = @Status";
                conn.Open();
                using (var multi = conn.QueryMultiple(sqlStr, new { Id = 11, Name = "打代码", Status = 99 }))
                {
                    //multi.IsConsumed   reader的状态 ,true 是已经释放
                    if (!multi.IsConsumed)
                    {
                        ////强类型
                        ////注意一个东西,Read获取的时候必须是按照上面返回表的顺序 (article,qqmodel,seotkd)
                        //var articleList = multi.Read<Temp>();//类不见得一定得和表名相同
                        //var QQModelList = multi.Read<QQModel>();
                        //var SeoTKDList = multi.Read<SeoTKD>();

                        ////动态类型
                        var articleList = multi.Read();
                        var QQModelList = multi.Read();
                        var SeoTKDList = multi.Read();

                        #region 输出
                        foreach (var item in QQModelList)
                        {
                            Console.WriteLine(item.Id + " " + item.Name + " " + item.Count);
                        }
                        foreach (var item in SeoTKDList)
                        {
                            Console.WriteLine(item.Id + " | " + item.SeoKeywords);
                        }
                        foreach (var item in articleList)
                        {
                            Console.WriteLine(item.Author);
                        }
                        #endregion
                    }

                }
            }

  

 

posted @ 2016-02-26 17:15 毒逆天 阅读(...) 评论(...) 编辑 收藏
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