使用Json.NET反序列化一个空数组 [英] Deserializing an empty array using Json.NET

问题描述

我有一个使用Json.NET v7.0.1的C#应用​​程序.作为REST调用的结果，我以以下形式获取了一些JSON:

I've got a C# application that uses Json.NET v7.0.1. As a result of a REST call, I get back some JSON in the form of:

{
"messages": [ {"phoneNumber":"123-456-7890", "smsText":"abcd1234="},
              {"phoneNumber":"234-567-8901", "smsText":"efgh5678="},
              {"phoneNumber":"345-678-9012", "smsText":"12345asdf"} ]
}

如果没有要返回的消息数据，我返回的JSON如下所示:

If there is no message data to return, the JSON that I get back looks like this:

{
"messages": [ ]
}

我的Message类看起来像这样:

My Message class looks like this:

public class Message
{
    public string PhoneNumber { get; set; }
    public string SmsText { get; set; }

    public Message()
    {
    }

    public Message(string phoneNumber, string smsText)
    {
        PhoneNumber = phoneNumber;
        SmsText = smsText;
    }
}

当我尝试反序列化JSON时，我正在使用以下代码:

When I try to deserialize the JSON, I'm using the following code:

Message[] messages = JsonConvert.DeserializeObject<Message[]>(json, new JsonSerializerSettings
{
    MissingMemberHandling = MissingMemberHandling.Ignore
});

我遇到的问题是在message数组为空时反序列化JSON.发生这种情况时，我得到以下异常:

The problem I'm running into is deserializing the JSON when the messages array is empty. When that occurs, I get the following exception:

无法反序列化当前JSON对象(例如{\"name \":\"value \"}) 变成类型"WindowsFormTestApplication.Message []"，因为类型 需要JSON数组(例如[1,2,3])才能正确反序列化.\ r \ nTo 修复此错误，或者将JSON更改为JSON数组(例如[1,2,3]) 或更改反序列化类型，使其成为普通的.NET类型(例如 不是像整数这样的原始类型，不是像数组这样的集合类型 或列表)，可以从JSON对象反序列化. 也可以将JsonObjectAttribute添加到类型中以强制将其 从JSON对象反序列化. 路径消息"，第2行，位置15.

Cannot deserialize the current JSON object (e.g. {\"name\":\"value\"}) into type 'WindowsFormTestApplication.Message[]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.\r\nTo fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object. Path 'messages', line 2, position 15.

当JSON数组为空时，我希望我的Message []变量为null.我是否需要定制转换器来进行反序列化，还是我遗漏了一些明显的东西?谢谢！

When the JSON array is empty, I'd like my Message[] variable to be null. Do I need a custom converter to get this deserialized or am I missing something obvious? Thanks!

推荐答案

您应该只发送一个数组

[ {"phoneNumber":"123-456-7890", "smsText":"abcd1234="},
              {"phoneNumber":"234-567-8901", "smsText":"efgh5678="},
              {"phoneNumber":"345-678-9012", "smsText":"12345asdf"} ]

或者使用像这样的包装对象

Or use some wrapper object like this

public WrapperObject 
{ 
    public Message[] messages { get; set; } 
}

然后使用它反序列化

var wrapper = JsonConvert.DeserializeObject<WrapperObject>(json, new JsonSerializerSettings
    {
        MissingMemberHandling = MissingMemberHandling.Ignore
    });

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