C# Declare variable in lambda expression

Question

I want to do a simple lambda expression like this:

IList list = GetSomeList();

MyEntity1 result = list.SingleOrDefault(         


        

Answer 1

You can use the Select operator:

IList list = GetSomeList();

MyEntity1 result = list
    .Select(x => new { Item = x, Entity2 = GetMyEntity2(x) })    
    .SingleOrDefault(x => x.Entity2 != null && x.Entity2.Id != null && x.Entity2.Id > 0);

Or, since you're not even using the Item after pushing it through GetMyEntity2 you could just have:

MyEntity1 result = list
    .Select(x => GetMyEntity2(x))    
    .SingleOrDefault(x => x != null && x.Id != null && x.Id > 0);