如何将 StreamingContext 传递给 DataContractSerializer？

Question

我正在尝试将一些数据传递给 DataContractSerializer 的 StreamingContext，但我不知道如何。 这是我的代码的一个小示例：

MemoryStream stream = new MemoryStream();
DataContractSerializer serializer = new DataContractSerializer(typeof(OldClass));
serializer.WriteObject(stream, _OldClass);
stream.Seek(0, SeekOrigin.Begin);

serializer = new DataContractSerializer(typeof(NewClass));
    //here I would like to give the serializer e.g. a string as StreamingContext.Context
_NewClass = (NewClass)serializer.ReadObject(stream);

Answer 1

你不能。

当使用DataContractSerializer，StreamingContext 实例，被传递给序列化/反序列化回调，来自内部XmlObjectSerializerContext。

这里是初始化代码：

internal XmlObjectSerializerContext(DataContractSerializer serializer, DataContract rootTypeDataContract, DataContractResolver dataContractResolver)  
    : this(serializer, serializer.MaxItemsInObjectGraph, new StreamingContext(StreamingContextStates.All), serializer.IgnoreExtensionDataObject, dataContractResolver)
{
    // ...
}

如您所见，这段代码创建了new StreamingContext(StreamingContextStates.All)。
为清楚起见，NetDataContractSerializer 的类似代码使用来自传递的序列化程序实例的上下文：

internal XmlObjectSerializerContext(NetDataContractSerializer serializer) 
    : this(serializer, serializer.MaxItemsInObjectGraph, serializer.Context, serializer.IgnoreExtensionDataObject)
{
}