如何在json.net中将空字符串反序列化为枚举 [英] How to handle deserialization of empty string into enum in json.net

问题描述

我正在将json属性反序列化为一个枚举，但是当该属性为空字符串时，在处理案例时遇到了问题.

I am deserializing json properties into an enum but I'm having issues handling cases when the property is an empty string.

将值"转换为"EnrollmentState"类型时出错

Error converting value "" to type 'EnrollmentState'

我正在尝试反序列化requiredItem中的state属性.

I'm trying to deserialize the state property in a requiredItem.

{
    "currentStage" : "Pre-Approved",
    "stages" : ["Applicant", "Pre-Approved", "Approved", "Enrolled"],
    "requiredItems" : [{
            "id" : 1,
            "name" : "Documents",
            "state" : "" 
        }, {
            "id" : 2,
            "name" : "Eligibility Verification",
            "state" : "complete"
        }, {
            "id" : 3,
            "name" : "Placement Information",
            "state" : "incomplete"
        }
    ]
}

RequiredItem类和枚举...

public class RequiredItem {

    /// <summary>
    /// Gets or sets the identifier.
    /// </summary>
    /// <value>The identifier.</value>
    public string id { get; set; }

    /// <summary>
    /// Gets or sets the name.
    /// </summary>
    /// <value>The name.</value>
    public string name { get; set; }

    /// <summary>
    /// Gets or sets the status.
    /// </summary>
    /// <value>The status.</value>
    [JsonProperty(ItemConverterType = typeof(StringEnumConverter))]
    public EnrollmentState state { get; set; }
}

[JsonConverter(typeof(StringEnumConverter))]
public enum EnrollmentState {

    [EnumMember(Value = "incomplete")]
    Incomplete,

    [EnumMember(Value = "actionNeeded")]
    ActionNeeded,

    [EnumMember(Value = "complete")]
    Complete
}

如何设置反序列化的默认值，以便将空字符串反序列化为EnrollmentState.Incomplete而不是抛出运行时错误?

How can I set a default value for the deserialization so that empty strings will be deserialized into EnrollmentState.Incomplete instead of throwing a runtime error?

推荐答案

如果需要，您需要实现自定义StringEnumConverter:

You need to implement custom StringEnumConverter if you want that:

public class EnrollmentStateEnumConverter : StringEnumConverter
{
    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        if (string.IsNullOrEmpty(reader.Value.ToString()))
            return EnrollmentState.Incomplete;

        return base.ReadJson(reader, objectType, existingValue, serializer);
    }
}

[JsonConverter(typeof(EnrollmentStateEnumConverter))]
public enum EnrollmentState
{
    [EnumMember(Value = "incomplete")]
    Incomplete,

    [EnumMember(Value = "actionNeeded")]
    ActionNeeded,

    [EnumMember(Value = "complete")]
    Complete
}

这篇关于如何在json.net中将空字符串反序列化为枚举的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！