使用LINQ选择具有唯一ID的对象作为另一种对象类型

Question

Using LINQ , I'm trying to select unique Customer 's as Person objects. I'm using JSON data in the following example but I'm working with POCO objects in C# . In this example, I chose JSON to keep things simple.

I have the following Customer list:

[
  {
     "id": 123,
     "name: "John Smith",
     "transactionDate": "2019-08-21T10:30",
     "amount": 8.50
  },
  {
     "id": 234,
     "name: "Jane Doe",
     "transactionDate": "2019-08-22T18:21",
     "amount": 75.00
  },
  {
     "id": 123,
     "name: "John Smith",
     "transactionDate": "2019-08-26T10:30",
     "amount": 10.00
  }
]

I want to get the unique customers as Person objects and the result, should look like this:

[
  {
     "id": 123,
     "name": "John Smith"
  },
  {
     "id": 234,
     "name": "Jane Doe"
  }
]

The following should give me the unique ID's.

var uniqueIds = customers.Select(x => x.id).Distinct();

How do I now extract unique Person 's from List<Customer>() ?

Answer 1

One way is to use GroupBy :

var uniquePersons = customers
    .GroupBy(c => new Person() {Id = c.Id, Name = c.Name})
    .Select(g => g.Key)
    .ToList();

Answer 2

The suggested answer or the other SO post didn't return the results I needed. Here's the code that worked.

var uniquePersons = customers
                        .Select(x => new Person() { Id = x.Id, Name = x.Name })
                        .GroupBy(g => g.Id)
                        .Select(x => x.First())
                        .ToList();

I'm not saying this is the best way but this is what gave me a unique list of Person from a list of Customer .

I'd love to hear suggestions or explanations whether this is the best way to handle it or why the suggested answer didn't produce a List<Person>() with unique persons.