Warning: file_get_contents(/data/phpspider/zhask/data//catemap/1/vb.net/14.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181

Warning: file_get_contents(/data/phpspider/zhask/data//catemap/1/cassandra/3.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181
vb.net中的linq和_Vb.net_Linq - Fatal编程技术网

vb.net中的linq和

vb.net中的linq和,vb.net,linq,Vb.net,Linq,我需要做一个查询,看起来像是SQL: SELECT CodProiect, SUM(Valoare) FROM DET WHERE CodProiect = 'cod_pr' GROUP BY CodProiect; 我怎样才能用LINQ写同样的东西 我尝试过这样做: dim gac1 = (From ac1 In t_detalii _ Where ac1!CodProiect = cod_pr1 _ Select ac1!Valoare).

我需要做一个查询,看起来像是SQL:

SELECT  CodProiect, SUM(Valoare)
FROM DET
WHERE CodProiect = 'cod_pr'
GROUP BY CodProiect;
我怎样才能用LINQ写同样的东西

我尝试过这样做:

dim gac1 = (From ac1 In t_detalii _
            Where ac1!CodProiect = cod_pr1 _
            Select ac1!Valoare).Sum(Function(ac1) ac1!Valoare)

但是它给了我一个错误“没有为'Double'类型找到默认成员”。

您需要选择ac1而不是ac1!Valoare(是属性本身,而不是对应的对象)

编辑

当然,您可以在查询中对其进行分组:

dim gac1 = (From ac1 In t_detalii _
                       Where ac1!CodProiect = cod_pr1 _
                       Group By ac1.CodProiect Into ac2
                       Select ac2.Sum(Function(ac2) ac2!Valoare)

(在这个方向上,我不熟悉vb.net语法,而且我在没有编译器支持atm的情况下编写它。

请查看我的编辑,可能会对您有所帮助。
dim gac1 = (From ac1 In t_detalii _
                       Where ac1!CodProiect = cod_pr1 _
                       Group By ac1.CodProiect Into ac2
                       Select ac2.Sum(Function(ac2) ac2!Valoare)