帮助完成简单的 Linq 计数语句

Question

var q = dc.tblHelpCentreQuestions.Where(c => c.userID == UserID);
q.OrderByDescending(c => c.dateSubmitted);

这工作正常，但我还需要返回从 tblHelpCentreReplies 返回的记录数，其中 QuestionID 等于 tblHelpCentreQuestions.ID。这对于我来说在 SQL 中很简单，有人可以告诉我这是如何在 LINQ to SQL 中完成的吗？

编辑

我已经得到了这样的信息：

var q = 
from question in dc.tblHelpCentreQuestions
join replies in dc.tblHelpCentreReplies on question.ID
    equals replies.ticketID
where question.userID == UserID
orderby question.dateSubmitted descending
select new { question, replies.Count() };

但是replies.Count()抛出：

无效的匿名类型成员 声明者。匿名类型成员 必须向会员申报 分配、简单名称或成员 访问。

Answer 1

var q = 
from question in dc.tblHelpCentreQuestions
join replies in dc.tblHelpCentreReplies on question.ID equals replies.ticketID
where question.userID == UserID
orderby question.dateSubmitted descending
select new { Question = question, RepliesCount = replies.Count()};

Answer 2

linq 查询如下所示：

var q =
    dc.tblHelpCentreQuestions.
        Where(question => question.userID == UserID).
        OrderByDescending(question => question.dateSubmitted).
        GroupJoin(
            dc.tblHelpCentreReplies,
            question => question.ID,
            replies => replies.ticketID,
            (question, replies) => new {Question = question, RepliesCount = replies.Count()});

更新
如果你有一个关系映射可能会更容易一些

var q =
    dc.tblHelpCentreQuestions.
        Where(question => question.userID == UserID).
        OrderByDescending(question => question.dateSubmitted).
        Select(question => new {Question = question, RepliesCount = question.Replies.Count()});

Answer 3

这比您想象的要容易:-)

var q = 
    from question in dc.tblHelpCentreQuestions
    where question.userID == UserID
    orderby question.dateSubmitted desc
    select new { question, question.Replies.Count() };