CODEWITHSUNDEEP
c#serialization
newcarcrazy
newcarcrazy

Reputation: 105

Avoid Using Class don't Support Serializable

Everyone:

I viewed a way of avoiding some using class don't support serializable. But I don't know the reason of using this method. So I posed the question here.

So the previous code likes following

    [Serializable]
    Class OutterClass
    {
        public UsingClass UsingClassMember
        {
            get;
            set;
        }
    }

So here, if I want to serialize the OutterClass, it will occur a exception because the UsingClass don't support serializing. Obviously, all the members in the OutterClass should support serializing if I want to serialize the OutterClass.

But if I modify the code as following. The serialize operation can be done successfully.

    [Serializable]
    Class OutterClass
    {
        [NonSerialized]
        private UsingClass m_UsingClassMember;
        public UsingClass UsingClassMember
        {
            get { return m_UsingClassMember; };
            set { m_UsingClassMember = value };
        }
    }

I don't know the reason of this modification. It seems that property UsingClassMember's serialization don't need to serialize the class UsingClass itself. Can anyone give me a explanation?

Thanks!

Upvotes: 3

Views: 520

Answers (4)

fcuesta
fcuesta

Reputation: 4520

BinaryFormatter and SoapFormatter only serialize fields, not properties. In your first example, the auto-implemented property generates a hidden field that is not serializable. The serializer sees this auto generated non serializable field and raise an exception.

In your second example, you mark the field as NonSerialized and the serializer ignore this field and can serialize your outter class.

Upvotes: 1

Damith
Damith

Reputation: 63065

You have good example of how to prevent C# auto property from serialization.

Attribute 'NonSerialized' is not valid on this declaration type. It is only valid on 'field' declarations.

so you can't set 'NonSerialized' on C# auto property but if the property with baking up field like your second example you can set it like you did. Then both property and field will not serialized.

In second case compiler will ignore the property because underline field is Non serialized and you will not get exception like first case.

If you want to serialize then you have to set Serializable property on UsingClass but if you don't need to serialize you can do as second method or by using [XmlIgnoreAttribute] on your auto property

Upvotes: 1

Matthew
Matthew

Reputation: 25743

When you serialize / deserialize something that contains the NonSerialized attribute, then the object that has that attribute isn't taken into consideration. When you deserialize it, the value of UsingClassMember will be null (or whatever the default is for your datatype)

Upvotes: 0

Andrey Shchekin
Andrey Shchekin

Reputation: 21599

You have to decide whether you want to serialize data in UsingClassMember or not.

If you want to serialize it, you mark UsingClass with [Serializable]. Later when deserializing your data you will get the value of this property as it was before the serialization.

If you do not want to serialize it, you mark corresponding field with [NonSerialized]. In this case, the property will be null after deserialization (unless custom deserialization is used).

Only you can decide which approach to choose based on the meaning of your property and the purpose of serialization in your use case.

Upvotes: 1

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