Linq,将多个记录组合成逗号分隔的字符串,按不同的值分组

Question

我正在尝试使用不同的groupby,然后构建一个csv字符串:

[FROM]是一对多联接:

        var allCustomerRoles = (from cr in Customers
                                join r in CustomerRoles
                                on cr.Role_ID equals r.Role_ID
                                select new { cr.Customer_No_, r.Role_ID });

所以问题是,您能否告诉我如何编写LINQ查询以达到[TO]结构,其中Customer_No_是不同的,并且它的Role_ID值被连接成CSV字符串.

Answer 1

谢谢@ reda-mattar,您的链接引导我找到解决方案,这就是我想要的:

var allCustomerRoles = (from cr in Customers
                        join r in Roles
                        on cr.Role_ID equals r.Role_ID
                        group r.Role_ID by cr.Customer_No_ into g
                        select new { Customer_No_ = g.Key, Role_ID = string.Join(",", g.ToArray()) });