如何将表达式传递给LINQ查询？

Question

I can pass an Expression into the LINQ Select() method:

public IQueryable<T> GetInfo(long limit, Expression<Func<MyType, T>> selector)
{
    return DbSet.Where(t => t.id < limit).Select(selector)
}

How can I do the same using LINQ-style query?

public IQueryable<T> GetInfo(long limit, Expression<Func<MyType, T>> selector)
{
    var result = from t in DbSet
                 where t.id < limit
                 select selector(t) // doesn't work
    return result
}

Answer 1

Well you can use:

var result = (from t in DbSet
             where t.id < limit
             select t).Select(selector);

... but you can't just use the selector inside the query expression, as that's implicitly wrapping an extra layer that you don't want.

It's not clear why you want to use query expressions here anyway, mind you - I would strongly recommend that you become comfortable with both styles of LINQ and use whatever's more appropriate at the time - which in this case is the style you have in your original code.