序列化期间出现异常 - 不应使用具有数据协定名称的类型

Question

我有这个类:

[DataContract]
class ClassA
{
    [DataMember]
    public Object Value; // and this can be of ClassB or some primitive type.
    ...
}

[DataContract]
class ClassB : IEnumerable<KeyValuePair<String, ClassA>>
{
    [DataMember]
    private Dictionary<String, ClassA> dictionary;
    ...
}

但在序列化发生时出现此异常：

Type 'MyNamespace.ClassA' with data contract name 'ClassA:http://schemas.datacontract.org/2004/07/MyNamespace' is not expected. 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.

我觉得我应该使用 KnownType 属性，但我不知道如何使用，因为我没有 IEnumerable<T>.

有人能帮忙吗？谢谢

Answer 1

尝试以下操作：

[DataContract]
[KnownType(typeof(int))]
// Same way add here all the types that you are using in your class A.
class ClassA
{
    [DataMember]
    public int Value;
    ...
}

Answer 2

我终于弄对了。解决方案非常简单，第一个 class 的 Value 是 Object 类型，序列化程序必须知道哪些类型将被装入 Object.

因此 ClassA 应声明为：

[DataContract]
[KnownType(typeof(ClassA)]
[KnownType(typeof(ClassB)]
class ClassA
{
    [DataMember]
    public Object Value; // ClassA or ClassB or some primitive type.
    ...
}

这份文件 here 确实有助于澄清什么是 KnownType。

序列化期间出现异常 - 不应使用具有数据协定名称的类型

Exception during the serialization - Type with data contract name is not expected

c#

serialization

datacontractserializer