如何从WCF REST方法返回自定义类型值的Dictionary作为常规JSON对象?

时间:2016-02-18 19:09:08

标签: c# json wcf rest

我们说我有一个看起来像这样的自定义类型:

[DataContract]
public class CompositeType
{
    [DataMember]
    public bool HasPaid
    {
        get;
        set;
    }

    [DataMember]
    public string Owner
    {
        get;
        set;
    }
}

和一个如下所示的WCF REST接口:

[ServiceContract]
public interface IService1
{
    [OperationContract]
    Dictionary<string, CompositeType> GetDict();
}

然后我如何让我的方法实现返回一个看起来像这样的JSON对象......

{"fred":{"HasPaid":false,"Owner":"Fred Millhouse"},"joe":{"HasPaid":false,"Owner":"Joe McWirter"},"bob":{"HasPaid":true,"Owner":"Bob Smith"}}

希望它看起来像这样:

[{"Key":"fred","Value":{"HasPaid":false,"Owner":"Fred Millhouse"}},{"Key":"joe","Value":{"HasPaid":false,"Owner":"Joe McWirter"}},{"Key":"bob","Value":{"HasPaid":true,"Owner":"Bob Smith"}}]

理想情况下,我不希望改变方法的返回类型。

我尝试了很多不同的方法,但找不到有效的解决方案。令人讨厌的是,使用Newtonsoft.Json在一行中生成正确形状的JSON对象结构很容易:

string json = JsonConvert.SerializeObject(dict);

其中dict定义为:

Dictionary<string, CompositeType> dict = new Dictionary<string, CompositeType>();
dict.Add("fred", new CompositeType { HasPaid = false, Owner = "Fred Millhouse" });
dict.Add("joe", new CompositeType { HasPaid = false, Owner = "Joe McWirter" });
dict.Add("bob", new CompositeType { HasPaid = true, Owner = "Bob Smith" });

但我不想从我的WCF方法返回一个字符串。这是因为它隐藏了返回的真实类型;并且因为WCF也序列化了字符串,导致转义双引号和其他丑陋,使得非.Net REST客户端难以解析。

1 个答案:

答案 0 :(得分:4)

这是响应@dbc评论的部分解决方案。它导致了这种形状正确的JSON结构......

{"fred":{"HasPaid":false,"Owner":"Fred Millhouse"},"joe":{"HasPaid":false,"Owner":"Joe McWirter"},"bob":{"HasPaid":true,"Owner":"Bob Smith"}}

但遗憾的是,必须将方法的返回类型更改为Message。界面变为:

[ServiceContract]
public interface IService1
{
    [OperationContract]
    Message GetDict();
}

,实施变为:

using Newtonsoft.Json;
...
[WebGet(ResponseFormat = WebMessageFormat.Json)]
public Message GetDict()
{
    Dictionary<string, CompositeType> dict = new Dictionary<string, CompositeType>();
    dict.Add("fred", new CompositeType { HasPaid = false, Owner = "Fred Millhouse" });
    dict.Add("joe", new CompositeType { HasPaid = false, Owner = "Joe McWirter" });
    dict.Add("bob", new CompositeType { HasPaid = true, Owner = "Bob Smith" });

    string json = JsonConvert.SerializeObject(dict);
    return WebOperationContext.Current.CreateTextResponse(json, "application/json; charset=utf-8", Encoding.UTF8);
}

需要注意的一个有用功能是,与返回Stream时不同,当您访问REST方法的URI时,可以在Web浏览器中轻松查看JSON。