如何使用Newtonsoft JSON序列化器忽略空数组元素 [英] How to ignore null array elements with Newtonsoft JSON serializer

问题描述

我正在尝试序列化对象数组，但是我需要它忽略空元素.我意识到我可以在反序列化时简单地拥有检查空值的逻辑，但是我不想在网络上写入不必要的数据.该数组最多可包含9个元素，但并非在所有实例中都使用所有9个索引.我知道可以使用列表，但是出于效率考虑，我不希望这样做.

I'm attempting to serialize an object array, but I need it to ignore null elements. I realize I could simply have logic upon deserialization that checks for the nulls, however I don't want to write unnecessary data over the network. The array can have a maximum of 9 elements, but all 9 indices are not used in every instance. I understand that a list could be utilized, but for efficiency sake I do not wish to do that.

对于我在该网站上浏览过的类似问题，我试图将以下标签添加到数组中: [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]

Per similar questions I've browsed on this site, I've attempted to add the following tag to the array: [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]

但是，这种方法不会忽略null元素.

However, this approach does not ignore null elements.

[JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
public Node[] Nodes { get; } 
public void Init() 
{
    Nodes = new Node[9];
}
public string Encode()
{
    return JsonConvert.SerializeObject(Nodes, Formatting.None);
}

是否有一个优雅的解决方案?

Is there an elegant solution to this?

推荐答案

最简单的解决方案是在序列化之前过滤数组.您可以在您的 Encode 方法中执行此操作，而无需实例化新数组:

The simplest solution is just to filter the array just before you serialize it. You can do this in your Encode method, without instantiating a new array:

public string Encode()
{
    return JsonConvert.SerializeObject(Nodes.Where(n => n != null), Formatting.None);
}

提琴: https://dotnetfiddle.net/dj8lnP

如果您不喜欢该主意，无论出于何种原因，都可以使用自定义序列化为JSON时不包含集合中的特定项类似进行过滤.

If you don't like that idea, for whatever reason, you can use a custom JsonConverter similar to the one in Excluding specific items in a collection when serializing to JSON to do the filtering.

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