具有可以是两种不同类型之一的属性的类 [英] Class with property that can be one of two different types

问题描述

我正在用C＃开发Telegram机器人，但难以实现 Message 类型。根据 API文档，聊天字段可以是 User 类型，也可以是 GroupChat 类型。

I'm developing a Telegram bot in C# but have difficulty with implementing Message type. According to API documentation, chat field can be either of type User or of type GroupChat. How do I implement that in C#?

到目前为止，我只能使用 Newtonsoft.Json 提出以下代码：

So far I could only come up with following code using Newtonsoft.Json:

public class Update {
....
  [JsonProperty("chat")]
  public User chat { get; set; }

  [JsonProperty("chat")]
  public GroupChat group_chat { get; set; }
....
}

但它不适用于我的WebAPI 2控制器方法，因为我使用 FromBody 属性反序列化 Message ：

But it doesn't work with my WebAPI 2 controller method since I deserialize Message using FromBody attribute:

public async Task<HttpResponseMessage> Post(string token, [FromBody] Update update)

（类型 Update 的字段 message 的类型为 Message ）

(type Update has a field message of type Message)

是否有更好的方法来实现 Message 类型？

Is there any better way to implement Message type?

推荐答案

由于您应该在一个字段中处理看似完全不同的两个对象，所以我认为您不能使用强类型的对象，但可以对聊天字段使用动态类型，例如

Since you are supposed to handle seemingly two completely different objects in one field I don't think you can use strongly-typed objects but you can use a dynamic type for the chat field such as

public class Telegram
{
    public int message_id { get; set; }
    public dynamic chat { get; set; }
}

然后，您可以访问变量并检查它们是否为空了解是用户聊天还是群聊：

Then you can access the variables and check if they are null or not to understand if it's a user or a group chat:

static void Main(string[] args)
{
    string json = @"{ ""chat"": { ""id"": 1, ""first_name"": ""my_first_name"", ""last_name"": ""my_last_name"",  ""username"": ""my_username"" }, ""message_id"": 123 }";
    var telegram = Newtonsoft.Json.JsonConvert.DeserializeObject<Telegram>(json);
    string name = telegram.chat.first_name; // name = my_first_name
    string title = telegram.chat.title; // title = null
}

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