C#

Ennis Ray Lynch, Jr. wrote:

Objects have to have public, empty constructors to be serialization using the built in methods

Ennis Ray Lynch, Jr. wrote:

Base classes, in general, can't be serialized if they can't be instantiated.

Mark Salsbery
Microsoft MVP - Visual C++

Ennis Ray Lynch, Jr. wrote:

For standard XML serializaiton the default constructor needs to be public

Ennis Ray Lynch, Jr. wrote:

For binary serializaiton you need to have the serialization constructor defined.

Mark Salsbery
Microsoft MVP - Visual C++

public class Foo{

}

public class Foo{
    public Foo(){}
}

public class Foo{
    public Foo(int a){}
}

public class Foo{
    private Foo(){}
}

Ennis Ray Lynch, Jr. wrote:

a default constructor is defined by default unless you create either a non-default constructor or a default constructor with visibility other than public.

Mark Salsbery
Microsoft MVP - Visual C++

	[Serializable]
	public class Animal
	{
		public string str
		{
			get;
			set;
		}
	}

	[Serializable]
	public class Dog : Animal
	{
		[NonSerialized]  <code>//<-- Optional!</code>
		public Int32 A;

		[NonSerialized]  <code>//<-- Optional!</code>
		public Int32 B;

		public Dog()
		{
			A = 5;
			B = 10;
		}
	}

	sealed class DogToAnimalDeserializationBinder : SerializationBinder
	{
		public override Type BindToType(string assemblyName, string typeName)
		{
			Type typeToDeserialize = null;

			String assemVer1 = Assembly.GetExecutingAssembly().FullName;
			String typeVer1 = "Dog";

			if (assemblyName == assemVer1 && typeName == typeVer1)
			{
				typeName = "Animal";
			}

			// The following line of code returns the type.
			typeToDeserialize = Type.GetType(String.Format("{0}, {1}",
				typeName, assemblyName));

			return typeToDeserialize;
		}
	}

...

Dog dog = new Dog();
dog.A = 3;
dog.B = 5;
dog.str = "Animal String";

MemoryStream MemStream = new MemoryStream();

// Serialize a Dog object
BinaryFormatter Serializer = new BinaryFormatter();
Serializer.Serialize(MemStream, dog);

MemStream.Seek(0, SeekOrigin.Begin);

// Deserialize as an Animal object
Serializer.Binder = new DogToAnimalDeserializationBinder();
Animal animal = (Animal)Serializer.Deserialize(MemStream); 

Mark Salsbery
Microsoft MVP - Visual C++