反序列化时，标记为[NonSerialized]的字段会怎样？

Question

Are these fields set to default values like when a new instance is created? Can I create custom code to set these fields to new values upon deserialization?

Answer 1

Note: all of this is specific to BinaryFormatter :

By default, they are ignored completely; they will have their type-default values, ie a zero-value / null-value.

If you implement custom serialization ( ISerializable ), then [NonSerializable] doesn't apply, and you can do what you want, but most people don't want to have to do this. However, you can also implement IDeserializationCallback , which provides an ideal opportunity to initialize such fields:

[Serializable]
class Foo : IDeserializationCallback
{
    // ... not shown
    void IDeserializationCallback.OnDeserialization(object sender)
    {
        // init your [NonSerialized] fields here
    }
}

Note that other serializers have different implementations for serialization callbacks, some of which are also supported by BinaryFormatter , for example:

[Serializable]
class Foo
{
    // ... not shown
    [OnDeserializing]
    private void AnyMethodName(StreamingContext c)
    {
        // init your [NonSerialized] fields here
    }
}

The attribute-based callbacks provide more opportunities to inject code at specific points, and are usually preferred. There are 4: [OnDeserializing] , [OnDeserialized] , [OnSerializing] and [OnSerialized] .

Answer 2

When a new instance is creted this fields are default value of type.

You can set set your custom values on object construct