c# - 如何删除 linq 查询中的可重复项

Question

listOrders.DataSource = (from sp in dbdata.Specifications
                         join ord in dbdata.Orders on sp.O_id equals ord.O_id
                         join prd in dbdata.Products on ord.O_id equals prd.O_ID
                         where sp.Approve == "Yes" && 
                         sp.Awailable_BOM == "Yes" && 
                         prd.Hours_prd == null
                         orderby sp.O_id descending
                         select sp.O_id).Distinct();

在这里，我试图获得降级的价值。但它总是得到递增的值。如果我删除“Distinct()”它可以正常工作，但在添加“Distinct()”后会出现此问题。

Answer 1

尝试这个：

listOrders.DataSource = (from sp in dbdata.Specifications
                         join ord in dbdata.Orders on sp.O_id equals ord.O_id
                         join prd in dbdata.Products on ord.O_id equals prd.O_ID
                         where sp.Approve == "Yes" && 
                         sp.Awailable_BOM == "Yes" && 
                         prd.Hours_prd == null
                         select sp.O_id).Distinct().OrderByDescending();