C# 如何添加元数据来描述JSON.Net中哪些属性是日期_C#_Json_Date_Datetime_Json.net

C# 如何添加元数据来描述JSON.Net中哪些属性是日期

c# json date datetime

C# 如何添加元数据来描述JSON.Net中哪些属性是日期,c#,json,date,datetime,json.net,C#,Json,Date,Datetime,Json.net,我想在我的json中添加一个元数据属性，这样客户端就可以知道哪些属性是日期例如，如果我有这样一个对象： { "notADate": "a value", "aDate": "2017-04-23T18:25:43.511Z", "anotherDate": "2017-04-23T18:25:43.511Z" } { "_date_properties_": ["aDate", "anotherDate"], "notADate": "a value", "aDate

我想在我的json中添加一个元数据属性，这样客户端就可以知道哪些属性是日期

例如，如果我有这样一个对象：

{
  "notADate": "a value",
  "aDate": "2017-04-23T18:25:43.511Z",
  "anotherDate": "2017-04-23T18:25:43.511Z"
}

{
  "_date_properties_": ["aDate", "anotherDate"],
  "notADate": "a value",
  "aDate": "2017-04-23T18:25:43.511Z",
  "anotherDate": "2017-04-23T18:25:43.511Z"
}

我想添加一个元数据属性，告诉消费者哪些属性要作为日期处理，如下所示：

{
  "notADate": "a value",
  "aDate": "2017-04-23T18:25:43.511Z",
  "anotherDate": "2017-04-23T18:25:43.511Z"
}

{
  "_date_properties_": ["aDate", "anotherDate"],
  "notADate": "a value",
  "aDate": "2017-04-23T18:25:43.511Z",
  "anotherDate": "2017-04-23T18:25:43.511Z"
}

任何帮助都会很好，谢谢

您可以创建一个将合成的

“\u date\u properties\uu”

属性插入到每个序列化对象的协定中的

为此，第一个子类允许在应用程序添加的事件处理程序创建契约后，对其进行流畅的自定义：

public class ConfigurableContractResolver : DefaultContractResolver
{
    readonly object contractCreatedPadlock = new object();
    event EventHandler<ContractCreatedEventArgs> contractCreated;
    int contractCount = 0;

    void OnContractCreated(JsonContract contract, Type objectType)
    {
        EventHandler<ContractCreatedEventArgs> created;
        lock (contractCreatedPadlock)
        {
            contractCount++;
            created = contractCreated;
        }
        if (created != null)
        {
            created(this, new ContractCreatedEventArgs(contract, objectType));
        }
    }

    public event EventHandler<ContractCreatedEventArgs> ContractCreated
    {
        add
        {
            lock (contractCreatedPadlock)
            {
                if (contractCount > 0)
                {
                    throw new InvalidOperationException("ContractCreated events cannot be added after the first contract is generated.");
                }
                contractCreated += value;
            }
        }
        remove
        {
            lock (contractCreatedPadlock)
            {
                if (contractCount > 0)
                {
                    throw new InvalidOperationException("ContractCreated events cannot be removed after the first contract is generated.");
                }
                contractCreated -= value;
            }
        }  
    }

    protected override JsonContract CreateContract(Type objectType)
    {
        var contract = base.CreateContract(objectType);
        OnContractCreated(contract, objectType);
        return contract;
    }
}

public class ContractCreatedEventArgs : EventArgs
{
    public JsonContract Contract { get; private set; }
    public Type ObjectType { get; private set; }

    public ContractCreatedEventArgs(JsonContract contract, Type objectType)
    {
        this.Contract = contract;
        this.ObjectType = objectType;
    }
}

public static class ConfigurableContractResolverExtensions
{
    public static ConfigurableContractResolver Configure(this ConfigurableContractResolver resolver, EventHandler<ContractCreatedEventArgs> handler)
    {
        if (resolver == null || handler == null)
            throw new ArgumentNullException();
        resolver.ContractCreated += handler;
        return resolver;
    }
}

最后，按如下方式序列化示例类型：

var settings = new JsonSerializerSettings
{
    ContractResolver = new ConfigurableContractResolver
    {
        // Here I am using CamelCaseNamingStrategy as is shown in your JSON.
        // If you don't want camel case, leave NamingStrategy null.
        NamingStrategy = new CamelCaseNamingStrategy(),
    }.Configure((s, e) => { e.Contract.AddDateProperties(); }),
};

var json = JsonConvert.SerializeObject(example, Formatting.Indented, settings);

此解决方案仅处理静态类型的

DateTime

和

DateTime？

属性。如果您有

对象

值的属性，这些属性有时有

日期时间

值，或者有

字典

，或者包含

日期时间

值，则需要更复杂的解决方案

（作为替代实现，您可以使用

JsonContractExtensions.AddDateProperties（）对所需的属性进行子类化和硬编码。）

，但我认为创建一个通用的、可流畅配置的契约解析器会更有趣，以防以后需要插入不同的定制。）

您可能希望获得最佳性能

示例。