我有一个简单的数据模型，涉及到杂草和杂草家族。
WeedFamily <-1---*-> Weed（WeedFamily 和 Weed 之间是一对多关系）
我正在尝试完成我的第一个 ApiController，以便可以轻松地检索我的数据作为 JSON，供 AngularJS 应用程序使用。当我在应用程序中访问 /WeedAPI/ URL 时，会出现以下错误。我相信问题是我在Weed和WeedFamily之间存在循环引用导致的。
我该如何更改我的数据模型，以便在保持Weed-WeedFamily双向质量的同时使 JSON 序列化工作？
(也就是说，我仍然希望能够构建以下表达式：
WeedData.GetFamilies()["mustard"].Weeds.Count
WeedData.GetWeeds()[3].Family.Weeds
错误：
<Error>
<Message>An error has occurred.</Message>
<ExceptionMessage>
The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'.
</ExceptionMessage>
<ExceptionType>System.InvalidOperationException</ExceptionType>
<StackTrace/>
<InnerException>
<Message>An error has occurred.</Message>
<ExceptionMessage>
Object graph for type 'WeedCards.Models.WeedFamily' contains cycles and cannot be serialized if reference tracking is disabled.
</ExceptionMessage>
<ExceptionType>
System.Runtime.Serialization.SerializationException
</ExceptionType>
<StackTrace>
at System.Runtime.Serialization.XmlObjectSerializerWriteContext.OnHandleReference(XmlWriterDelegator xmlWriter, Object obj, Boolean canContainCyclicReference) at WriteWeedToXml(XmlWriterDelegator , Object , XmlObjectSerializerWriteContext , ClassDataContract ) at System.Runtime.Serialization.ClassDataContract.WriteXmlValue(XmlWriterDelegator xmlWriter, Object obj, XmlObjectSerializerWriteContext context) at System.Runtime.Serialization.XmlObjectSerializerWriteContext.WriteDataContractValue(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle) at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithoutXsiType(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle) at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerialize(XmlWriterDelegator xmlWriter, Object obj, Boolean isDecl...etc
</StackTrace>
</InnerException>
</Error>
我的数据：
public class WeedData
{
public static Dictionary<string,WeedFamily> GetFamilies(){
return new Dictionary<string,WeedFamily>
{
{"mustard",new WeedFamily("Mustard","Brassicaceae")}
,{"pigweed",new WeedFamily("Pigweed","Amaranthus")}
,{"sunflower",new WeedFamily("Sunflower","Asteraceae")}
};
}
public static List<Weed> GetWeeds(){
var Families = GetFamilies();
return new List<Weed>
{
new Weed("Hairy Bittercress","Cardamine hirsuta",Families["mustard"])
,new Weed("Little Bittercress","Cardamine oligosperma",Families["mustard"])
,new Weed("Shepherd's-Purse","Capsella bursa-pastoris",Families["mustard"])
,new Weed("Wild Mustard","Sinapis arvensis / Brassica kaber",Families["mustard"])
,new Weed("Wild Radish","Raphanus raphanistrum",Families["mustard"])
,new Weed("Radish","Raphanus sativus",Families["mustard"])
,new Weed("Redroot Pigweed","Amaranthus retroflexus",Families["pigweed"])
,new Weed("Prickly Lettuce","Lactuca serriola",Families["sunflower"])
,new Weed("Spiny Sowthistle","Sonchus asper",Families["sunflower"])
,new Weed("Annual Sowthistle","Sonchus oleraceus",Families["sunflower"])
};
}
}
我的模型类：
[Serializable]
public class Weed
{
public string CommonName;
public string LatinName;
public List<WeedPhoto> Photos;
public WeedFamily Family;
public Weed(string commonName, string latinName)
{
CommonName = commonName;
LatinName = latinName;
}
public Weed(string commonName, string latinName, WeedFamily family)
{
CommonName = commonName;
LatinName = latinName;
Family = family;
Family.Weeds.Add(this);
}
override public string ToString()
{
return CommonName + " (" + LatinName + ")";
}
}
和
[Serializable]
public class WeedFamily
{
public string CommonName;
public string LatinName;
public List<Weed> Weeds;
public WeedFamily(string commonName, string latinName)
{
CommonName = commonName;
LatinName = latinName;
Weeds = new List<Weed>();
}
}
最后，ApiController：
public class WeedAPIController : ApiController
{
//
// GET: /WeedAPI/
public IEnumerable<Weed> GetAllWeeds()
{
return WeedData.GetWeeds();
}
}
ToString()方法？你可能只需要使用[DebuggerDisplay]特性。 - ANeves