newtonsoft jsonconverter-将属性重命名为其他属性的值

我的方法是编写自己的转换器。转换器只是以与普通转换器相同的方式进行序列化,但是每当它遇到属性上的特殊属性时,它应该在输出中重命名该属性。

因此,对C对象进行序列化如下:

1. 首先将C对象转换为JSON对象(即jtokens结构)。
2. 运行C对象中的属性,找到需要重命名的属性…
3. 对于这些属性中的每一个,确定它们的当前名称和新名称。
4. 对JSON对象执行重命名。
5. 最后将JSON对象序列化为字符串。

我已经做了一个简单的实现。用法如下:

class Program
{
    static void Main(string[] args)
    {
        var valueInt = new ValueInteger
        {
            ValueName = "mycounter",
            Value = 7,
            TimeStamp = 1010101010
        };

        var settings = new JsonSerializerSettings { Converters = new JsonConverter[] { new DynamicNameConverter() } };
        var result = JsonConvert.SerializeObject(valueInt, settings);
        Console.WriteLine(result);
        Console.Read();
    }
}


public class ValueInteger
{
    [JsonIgnore]
    public string ValueName { get; set; }

    [JsonDynamicName(nameof(ValueName))]
    public int Value { get; set; }

    [JsonProperty("timestamp")]
    public UInt64 TimeStamp { get; set; }
}

帮助程序类:

class DynamicNameConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        // Only use this converter for classes that contain properties with an JsonDynamicNameAttribute.
        return objectType.IsClass && objectType.GetProperties().Any(prop => prop.CustomAttributes.Any(attr => attr.AttributeType == typeof(JsonDynamicNameAttribute)));
    }

    public override bool CanRead => false;
    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        // We do not support deserialization.
        throw new NotImplementedException();
    }

    public override bool CanWrite => true;
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        var token = JToken.FromObject(value);
        if (token.Type != JTokenType.Object)
        {
            // We should never reach this point because CanConvert() only allows objects with JsonPropertyDynamicNameAttribute to pass through.
            throw new Exception("Token to be serialized was unexpectedly not an object.");
        }

        JObject o = (JObject)token;
        var propertiesWithDynamicNameAttribute = value.GetType().GetProperties().Where(
            prop => prop.CustomAttributes.Any(attr => attr.AttributeType == typeof(JsonDynamicNameAttribute))
        );

        foreach (var property in propertiesWithDynamicNameAttribute)
        {
            var dynamicAttributeData = property.CustomAttributes.FirstOrDefault(attr => attr.AttributeType == typeof(JsonDynamicNameAttribute));

            // Determine what we should rename the property from and to.
            var currentName = property.Name;
            var propertyNameContainingNewName = (string)dynamicAttributeData.ConstructorArguments[0].Value;
            var newName = (string)value.GetType().GetProperty(propertyNameContainingNewName).GetValue(value);

            // Perform the renaming in the JSON object.
            var currentJsonPropertyValue = o[currentName];
            var newJsonProperty = new JProperty(newName, currentJsonPropertyValue);
            currentJsonPropertyValue.Parent.Replace(newJsonProperty);
        }

        token.WriteTo(writer);
    }
}

[AttributeUsage(AttributeTargets.Property, Inherited = false, AllowMultiple = false)]
class JsonDynamicNameAttribute : Attribute
{
    public string ObjectPropertyName { get; }
    public JsonDynamicNameAttribute(string objectPropertyName)
    {
        ObjectPropertyName = objectPropertyName;
    }
}

请注意,可能会进行大量的错误处理 DynamicNameConverter 但我把它省去了,这样更容易阅读和理解。