代码之家 › 专栏 › 技术社区 › felixfbecker

如何在C#中序列化PSObjectJSON.NET?

json.net powershell c#

felixfbecker · 技术社区 · 7 年前

我正在编写Cmdlet,需要将对象结构传递到可能包含 PSObject s、目前,这些字符串序列化为包含CLIXML的JSON字符串。相反,我需要将其视为对象(包括中的NoteProperties) PSObject.Properties 作为属性,并递归序列化它们的值)。

我试着自己写 JsonConverter 但由于某些原因,它只会被调用为顶级对象,而不是嵌套对象 P对象

public class PSObjectJsonConverter : JsonConverter {

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) {
        if (value is PSObject) {
            JObject obj = new JObject();
            foreach (var prop in ((PSObject)value).Properties) {
                obj.Add(new JProperty(prop.Name, value));
            }
            obj.WriteTo(writer);
        } else {
            JToken token = JToken.FromObject(value);
            token.WriteTo(writer);
        }
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) {
        throw new NotImplementedException();
    }

    public override bool CanRead {
        get { return false; }
    }

    public override bool CanConvert(Type objectType) {
        return true;
    }
}

CamelCasePropertyNamesContractResolver . 有没有办法让转换器尊重这一点?

1 回复 | 直到 7 年前

dbc 7 年前

以下转换器应正确序列化类型为的递归嵌套对象 PSObject :

public class PSObjectJsonConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return typeof(PSObject).IsAssignableFrom(objectType);
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        var psObj = (PSObject)value;
        writer.WriteStartObject();
        foreach (var prop in psObj.Properties)
        {
            //Probably we shouldn't try to serialize a property that can't be read.
            //https://docs.microsoft.com/en-us/dotnet/api/system.management.automation.pspropertyinfo.isgettable?view=powershellsdk-1.1.0#System_Management_Automation_PSPropertyInfo_IsGettable
            if (!prop.IsGettable)
                continue;           
            writer.WritePropertyName(prop.Name);
            serializer.Serialize(writer, prop.Value);
        }
        writer.WriteEndObject();
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        throw new NotImplementedException();
    }

    public override bool CanRead { get { return false; } }
}

笔记:

在 WriteJson value prop.Value .
只要回来 true CanConvert() 当传入对象类型为 P对象 P对象 输入 WriteJson() .
JToken.FromObject(value) JsonSerializer serializer . 因此,任何 JsonSerializerSettings (包括转换器)将丢失。理论上你可以 JToken.FromObject(Object, JsonSerializer) 相反,这将保留设置,但如果这样做,则会遇到中描述的错误 JSON.Net throws StackOverflowException when using [JsonConvert()] . 幸运的是,既然我们现在回来了 false 从 CanConvert
不需要构造中间层 JObject JsonWriter ,性能会更好一些。

更新 另外,我正在使用序列化来使用 CamelCasePropertyNamesContractResolver . 有没有办法让转换器尊重这一点?

custom JsonConverter 对于您的类型,您需要手动执行所有操作,包括重新映射属性名。以下是 WriteJson() DefaultContractResolver.NamingStrategy

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        var psObj = (PSObject)value;
        writer.WriteStartObject();
        var resolver = serializer.ContractResolver as DefaultContractResolver;
        var strategy = (resolver == null ? null : resolver.NamingStrategy) ?? new DefaultNamingStrategy();

        foreach (var prop in psObj.Properties)
        {
            //Probably we shouldn't try to serialize a property that can't be read.
            //https://docs.microsoft.com/en-us/dotnet/api/system.management.automation.pspropertyinfo.isgettable?view=powershellsdk-1.1.0#System_Management_Automation_PSPropertyInfo_IsGettable
            if (!prop.IsGettable)
                continue;
            writer.WritePropertyName(strategy.GetPropertyName(prop.Name, false));
            serializer.Serialize(writer, prop.Value);
        }
        writer.WriteEndObject();
    }

Json.NET 9.0.1 因此,如果您使用的是早期版本,则需要创建自己的camel case名称映射器,如中所示 this answer