.net 使用 DataContractSerializer 的“非预期类型” - 但它只是一个简单的类，没有有趣的东西？
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"Type not expected", using DataContractSerializer - but it's just a simple class, no funny stuff?
提问by Julian
I'm refactoring my XML-serialization, and figured I'd try the DataContractSerializer. Everything runs smoothly, until it needs to serialize this class:
我正在重构我的 XML 序列化，并认为我会尝试 DataContractSerializer。一切运行顺利，直到它需要序列化这个类：
using System;
using System.Runtime.Serialization;
namespace VDB_Sync.Model
{
[DataContract(Name="Konstant")]
public class Konstant : DataFelt
{
[DataMember]
private MySqlDbType mydataType;
[DataMember]
private object value;
public Konstant(string navn, MySqlDbType dataType, object value)
: base(navn, dataType, "*Konstant", false, false)
{
//this.navn = navn;
this.mydataType = dataType;
this.value = value;
if (navn.Contains("*L?benummer"))
{
navn = "*Konstant: " + Convert.ToString(value);
}
}
public object Value
{
get
{
return value;
}
}
}
}
It give's me this:
它给了我这个：
Type 'VDB_Sync.Model.Konstant' with data contract name 'Konstant:http://schemas.datacontract.org/2004/07/VDB_Sync.Model' is not expected. Consider using a DataContractResolver or add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer.
不应使用数据合同名称“Konstant:http://schemas.datacontract.org/2004/07/VDB_Sync.Model”键入“VDB_Sync.Model.Konstant”。考虑使用 DataContractResolver 或将任何静态未知的类型添加到已知类型列表中 - 例如，通过使用 KnownTypeAttribute 属性或将它们添加到传递给 DataContractSerializer 的已知类型列表中。
*The help I've found so far points to collections and Types. I do have an enum (MySqlDbType) in my class - but get this: I even get the same error when i have no DataMembers declared at all :-x So - what's going on here? What am I missing?
*到目前为止我发现的帮助指向集合和类型。我的班级中有一个 enum (MySqlDbType) - 但是得到这个：当我根本没有声明 DataMembers 时，我什至得到同样的错误:-x 那么 - 这里发生了什么？我错过了什么？
for reference, this is how i serialized it, VDB_SessionController being the root:*
作为参考，这是我序列化它的方式，VDB_SessionController 是根：*
public void GemKonfig(VDB_SessionController session)
{
var settings = new XmlWriterSettings()
{
Indent = true,
IndentChars = "\t"
};
var writer = XmlWriter.Create(defaultFile, settings);
DataContractSerializer ser =
new DataContractSerializer(typeof(VDB_SessionController));
ser.WriteObject(writer, session);
writer.Close();
}
回答by competent_tech
The exception that is being reported is for VDB_Sync.Model.Konstant. This means that somewhere further up the chain, this class is being pulled into another class and that class is the one being serialized.
正在报告的例外是 VDB_Sync.Model.Konstant。这意味着在链上的某个地方，这个类被拉入另一个类，而那个类是被序列化的类。
The issue is that depending on how Konstant is embedded in this class (for example, if it is in a collection or a generic list), the DataContractSerializer may not be prepared for its appearance during deserialization.
问题在于，根据 Konstant 在此类中的嵌入方式（例如，如果它位于集合或通用列表中），DataContractSerializer 在反序列化期间可能未准备好出现。
To resolve this, you need to apply the known-type attribute to the class that contains Konstant. Based on your serialization code, I suspect that this is VDB_SessionController.
要解决此问题，您需要将 known-type 属性应用于包含 Konstant 的类。根据您的序列化代码，我怀疑这是VDB_SessionController.
So, try decorating this class with the KnownType attribute:
因此，尝试使用KnownType 属性装饰这个类：
[KnownType(typeof(VDB_Sync.Model.Konstant)]
public class VDB_SessionController
回答by fenix2222
Add this to WebApiConfig.cs
将此添加到 WebApiConfig.cs
GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
var json = config.Formatters.JsonFormatter;
json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects;
config.Formatters.Remove(config.Formatters.XmlFormatter);
参考：http: //www.datazx.cn/Forums/en-US/a5adf07b-e622-4a12-872d-40c753417645/action?threadDisplayName= web-api-error-the-objectcontent1-type-failed-to-serialize- the-response-body-for-content&forum=wcf
回答by dcastro
You can also combine [KnownType]and reflection to make your code more resistant to future changes.
您还可以结合[KnownType]和反射使您的代码更能抵抗未来的变化。
[DataContract]
[KnownType("GetKnownPersonTypes")]
internal class Person
{
private static IEnumerable<Type> _personTypes;
private static IEnumerable<Type> GetKnownTypes()
{
if (_personTypes == null)
_personTypes = Assembly.GetExecutingAssembly()
.GetTypes()
.Where(t => typeof (Person).IsAssignableFrom(t))
.ToList();
return _personTypes;
}
}
Now a DataContractSerializer/ DataContractJsonSerializer/ XmlSerializerconfigured to work with Person, will also work with anytype derived from Person(as long as it's declared within the same assembly).
现在DataContractSerializer/ DataContractJsonSerializer/XmlSerializer配置工作与Person，也将与工作的任何衍生类型Person（只要它是在同一组件内声明的）。
回答by gethomast
use KnownTypeAttribute for resolving DataFelt class. see: http://msdn.microsoft.com/en-us/library/system.runtime.serialization.knowntypeattribute.aspx
使用KnownTypeAttribute 来解析DataFelt 类。请参阅：http: //msdn.microsoft.com/en-us/library/system.runtime.serialization.knowntypeattribute.aspx
回答by fluidguid
The problem for me was that I was returning the Interface (IIndividual) from my WebAPI controller. When I changed that return type to the Class (Individual) type, this error went away.
我的问题是我从我的 WebAPI 控制器返回接口（IIndividual）。当我将该返回类型更改为 Class (Individual) 类型时，此错误消失了。
Not working:
不工作：
[HttpGet]
[Route("api/v1/Individual/Get/{id}")]
public IIndividual Get([FromUri]int id)
{
return _individualService.Get(id);
}
Working:
在职的：
[HttpGet]
[Route("api/v1/Individual/Get/{id}")]
public Individual Get([FromUri]int id)
{
IIndividual individual = _individualService.Get(id);
return individual as Individual;
}
回答by Sohayb Hassoun
It is like as @Leon suggested but with the fix from @Bryan, the 'KnownTypeAttribute' should be on the base class, so it should be like this:
就像@Leon 建议的那样，但是通过@Bryan 的修复，'KnownTypeAttribute' 应该在基类上，所以它应该是这样的：
[DataContract(Name="DataFelt")]
[KnownType(typeof(somenamespace.Konstant))]
public class DataFelt
and in the Subclass:
在子类中：
[DataContract(Name="Konstant")]
public class Konstant : DataFelt
回答by Leon
Change this:
改变这个：
[DataContract(Name="Konstant")]
public class Konstant : DataFelt
to this:
对此：
[DataContract(Name="Konstant")]
[KnownTypes(typeof(somenamespace.DataFelt))]
public class Konstant : DataFelt
