我有一个涉及杂草和杂草家庭的简单数据模型。
WeedFamily <-1---*-> Weed（WeedFamily 和 Weed 是一对多的关系）
我正在尝试完成我的第一个 ApiController，以便我可以轻松地将我的数据检索为 JSON 用于 AngularJS 应用程序。当我/WeedAPI/在我的应用程序中访问 URL 时，我收到以下错误。我很确定问题是我在Weedand之间有循环引用WeedFamily。
Weed我应该如何更改我的数据模型，以便 JSON 序列化能够工作，同时保持-关系的双向质量WeedFamily？
（即。我希望仍然能够构建如下表达式：
WeedData.GetFamilies()["mustard"].Weeds.Count
和
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();
}
}