如何结合这两个LINQ语句？

Question

How can I combine these two LINQ statements into one?

var Priority = repository.GetMany<Letter>(l => l.UserID == currentUser.ID)
                         .Select(l => l.Priority)
                         .FirstOrDefault();
var User = repository.GetMany<Letter>(l => l.Priority > Priority)
                     .Select(l => l.User)
                     .FirstOrDefault();

I need to get Priority of the currentUser and then get the next user that has the next Priority. For example, if the Priority of currentUser is 1, I need to get the user with Priority == 2.

Example:

letter=new letter { 
    User=Mark, Priority=1
    User=Raha, Priority=2
    User=Searah, Priority=3
}

when currentUser is Mark with Priority=1,i need to get user with Priority=2,in this sample Raha!

Answer 1

Assuming that your GetMany are indeed just Where calls, and therefore they returns an IQueryable, the following should do the trick I think:

var users = repository
    .GetMany<Letter>(l => l.Priority > (
        repository.GetMany<Letter>(
            l2 => l2.UserID = currentUser.ID
        )
        .Select(l2 => l2.Priority)
        .First()
    )
    .OrderBy(l => l.Priority)
    .Select(l => l.User)
    .Take(1);

Your first query is basically just inserted in the second query.