Question

我有一个使用1个表+大量视图的LINQ查询。我希望能够写出这样的东西：

IQueryable<Guid> mostViewedWriters;

switch (datePicker)
{
    case DatePicker.Last12Hours:
        mostViewedWriters = from x in context.tempMostViewed12Hours
                            select x.GuidId;
        break;
    case DatePicker.Last24Hours:
        mostViewedWriters = from x in context.tempMostViewed24Hours
                            select x.GuidId;
        break;
    case DatePicker.Last36Hours:
        mostViewedWriters = from x in context.tempMostViewed36Hours
                            select x.GuidId;
        break;
}

var query = from x1 in context.Articles
join x2 in context.Authors on x1.AuthorId == x2.AuthorId
join x3 in mostViewedWriters on x2.AuthorId == x3.Id
select new { x2.AuthorName, x1.ArticleId, x1.ArticleTitle };

上面的C＃是用来保护无辜者（我）的伪代码。问题的要点是：我有一个与视图结果相关的查询。然而，这种观点可能是许多不同观点之一。所有视图都返回相同的数据类型。我认为我可能能够创建一个IQueryable，它包含我需要的ID并使用该查询。唉，这种努力已经停滞不前。

Answer 1

你的问题是mostViewedWriters没有命名字段，因为它只是一个返回Guid列表的集合/查询，所以你应该像这样重写你的查询：

var query = from article in context.Articles
            join author in context.Authors on article.AuthorId == author.AuthorId
            join id in mostViewedWriters on author.AuthorId == id
            select new { x2.AuthorName, x1.ArticleId, x1.ArticleTitle };

第二个连接条件直接连接到行的值，因为它只是一个Guid。（我也改变了你的变量名，试图让它更清晰一点）

如何将LINQ查询与IQueryable <guid> </guid>组合在一起

1 个答案: