Left join on two Lists and maintain one property from the right with Linq

Question

I have 2 lists of the same type. The left list:

var leftList = new List();
leftList.Add(new Person {Id = 1, Name = \"John\", Chang         


        

Answer 1

Why don't you try a solution like this:

var query = (from left in leftList
    join right in rightList on left.Id equals right.Id into joinedList
    from sub in joinedList.DefaultIfEmpty()
    select new Person { 
        Id = left.Id,
        Name = left.Name,
        Changed = sub == null ? left.Changed : sub.Changed }).ToList();