对于任何在22年5月就需要。net 6解决方案并且仍在使用Newtonsoft的人来说，你可以像这样全局注册转换器:

var builder = WebApplication.CreateBuilder(args);
...
builder.Services.AddControllers(options => options.RespectBrowserAcceptHeader = true)
.AddNewtonsoftJson(opt =>
{
    opt.SerializerSettings.ContractResolver = new DefaultContractResolver();
    opt.SerializerSettings.Converters.Add(new Newtonsoft.Json.Converters.StringEnumConverter());
})
.AddXmlSerializerFormatters()
.AddXmlDataContractSerializerFormatters();

这很容易做到，只需向Gender属性添加一个ScriptIgnore属性，使其不被序列化，并添加一个被序列化的GenderString属性:

class Person
{
    int Age { get; set; }

    [ScriptIgnore]
    Gender Gender { get; set; }

    string GenderString { get { return Gender.ToString(); } }
}

用这个:

using Newtonsoft.Json;
using Newtonsoft.Json.Converters;

[Serializable]
[JsonConverter(typeof(StringEnumConverter))]
public enum Gender { Male, Female }

一个稍微更经得起考验的选择

面对同样的问题，我们决定需要一个自定义版本的StringEnumConverter，以确保枚举值可以随着时间的推移而扩展，而不会在反序列化方面发生灾难性的破坏(参见下面的背景)。使用下面的SafeEnumConverter允许反序列化完成，即使有效负载包含没有命名定义的枚举的值，这更接近于int-to-enum转换的工作方式。

用法:

[SafeEnumConverter]
public enum Colors
{
    Red,
    Green,
    Blue,
    Unsupported = -1
}

or

[SafeEnumConverter((int) Colors.Blue)]
public enum Colors
{
    Red,
    Green,
    Blue
}

来源:

public class SafeEnumConverter : StringEnumConverter
{
    private readonly int _defaultValue;

    public SafeEnumConverter()
    {
        // if you've been careful to *always* create enums with `0` reserved
        // as an unknown/default value (which you should), you could use 0 here. 
        _defaultValue = -1;
    }

    public SafeEnumConverter(int defaultValue)
    {
        _defaultValue = defaultValue;
    }

    /// <summary>
    /// Reads the provided JSON and attempts to convert using StringEnumConverter. If that fails set the value to the default value.
    /// </summary>
    /// <returns>The deserialized value of the enum if it exists or the default value if it does not.</returns>
    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        try
        {
            return base.ReadJson(reader, objectType, existingValue, serializer);
        }
        catch
        {
            return Enum.Parse(objectType, $"{_defaultValue}");
        }
    }

    public override bool CanConvert(Type objectType)
    {
        return base.CanConvert(objectType) && objectType.GetTypeInfo().IsEnum;
    }
}

背景

当我们考虑使用StringEnumConverter时，我们遇到的问题是，当添加了一个新的enum值时，我们还需要被动式，但并不是每个客户端都能立即意识到新值。在这些情况下，与Newtonsoft JSON打包的StringEnumConverter抛出类似于“将SomeString值转换为EnumType类型错误”的JsonSerializationException，然后整个反序列化过程失败。这对我们来说是一个问题，因为即使客户端计划忽略/丢弃它不理解的属性值，它仍然需要能够反序列化剩余的有效负载!

        Person p = new Person();
        p.Age = 35;
        p.Gender = Gender.Male;
        //1.  male="Male";
        string male = Gender.Male.ToString();

        p.Gender = Gender.Female;

        //2.  female="Female";
        string female = Enum.GetName(typeof(Gender), p.Gender);

        JObject jobj = new JObject();
        jobj["Age"] = p.Age;
        jobj["Gender"] = male;
        jobj["Gender2"] = female;

        //you result:  josn= {"Age": 35,"Gender": "Male","Gender2": "Female"}
        string json = jobj.ToString();

Asp。Net Core 3与System.Text.Json

public void ConfigureServices(IServiceCollection services)
{

    services
        .AddControllers()
        .AddJsonOptions(options => 
           options.JsonSerializerOptions.Converters.Add(new JsonStringEnumConverter())
        );

    //...
 }