忽略 Json.net 中的空字段 [英] Ignoring null fields in Json.net

问题描述

我有一些数据必须序列化为 JSON.我正在使用 JSON.NET.我的代码结构是这样的:

I have some data that I have to serialize to JSON. I'm using JSON.NET. My code structure is similar to this:

public struct structA
{
    public string Field1;
    public structB Field2;
    public structB Field3;
}

public struct structB
{
    public string Subfield1;
    public string Subfield2;
}

问题是，我的 JSON 输出只需要 Field1 OR Field2 OR Field3 - 这取决于使用哪个字段(即不是空值).默认情况下，我的 JSON 如下所示:

Problem is, my JSON output needs to have ONLY Field1 OR Field2 OR Field3 - it depends on which field is used (i.e. not null). By default, my JSON looks like this:

{
    "Field1": null,
    "Field2": {"Subfield1": "test1", "Subfield2": "test2"},
    "Field3": {"Subfield1": null, "Subfield2": null},
}

我知道我可以使用 NullValueHandling.Ignore，但这给了我看起来像这样的 JSON:

I know I can use NullValueHandling.Ignore, but that gives me JSON that looks like this:

{
    "Field2": {"Subfield1": "test1", "Subfield2": "test2"},
    "Field3": {}
}

我需要的是这个:

{
    "Field2": {"Subfield1": "test1", "Subfield2": "test2"},
}

有没有简单的方法来实现这一目标?

Is there simple way to achieve this?

推荐答案

是的，您需要使用 JsonSerializerSettings.NullValueHandling = NullValueHandling.Ignore.

但是因为结构是值类型，您需要标记 Field2, Field3 nullable 以获得预期结果:

But because structs are value types you need to mark Field2, Field3 nullable to get the expected result:

public struct structA
{
    public string Field1;
    public structB? Field2;
    public structB? Field3;
}

或者只是使用类而不是结构.

Or just use classes instead of structs.

文档:NullValueHandling 枚举

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