.NET Framework LINQ Left Outer Join
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Example
class Person
{
public string FirstName { get; set; }
public string LastName { get; set; }
}
class Pet
{
public string Name { get; set; }
public Person Owner { get; set; }
}
public static void Main(string[] args)
{
var magnus = new Person { FirstName = "Magnus", LastName = "Hedlund" };
var terry = new Person { FirstName = "Terry", LastName = "Adams" };
var barley = new Pet { Name = "Barley", Owner = terry };
var people = new[] { magnus, terry };
var pets = new[] { barley };
var query =
from person in people
join pet in pets on person equals pet.Owner into gj
from subpet in gj.DefaultIfEmpty()
select new
{
person.FirstName,
PetName = subpet?.Name ?? "-" // Use - if he has no pet
};
foreach (var p in query)
Console.WriteLine($"{p.FirstName}: {p.PetName}");
}
