在一個集合中，Select擴充方法是用來針對所下的條件，
根據該條件回傳指定型態的集合，請參考如下範例。
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| List<Person> personCollection = new List<Person>();
personCollection.Add(new Person(1, "Tim"));
personCollection.Add(new Person(2, "John"));
personCollection.Add(new Person(3, "brooke"));
IEnumerable<bool> a = personCollection.Select(x => x.Id == 2);
IEnumerable<Person> b = personCollection.Select(x => x);
IEnumerable<int> c = personCollection.Select(x => x.Id);
var carOwner = personCollection
.Where(x => x.Id == 2)
.Select(y => new Car { CarNo = "CAR-33456", Owner = y.Name })
.FirstOrDefault();
Console.ReadLine();
class Person
{
public int Id { get; set; }
public string Name { get; set; }
public Person(int id, string name)
{
Id = id;
Name = name;
}
}
class Car
{
public string? CarNo { get; set; }
public string? Owner { get; set; }
}
|
注意，使用之前需要先include System.Linq命名空間。
參考資料：
Enumerable.Select Method