How can I serialize an object that has an interface as a property?

Question

I have 2 interfaces IA and IB.

public interface IA
{
    IB InterfaceB { get; set;  }
}

public interface IB
{
    IA InterfaceA { get; set;  }

    void SetIA(IA value);
}

Each interfaces references the other.

I am trying to serialize ClassA as defined below.

[Serializable]
public class ClassA : IA
{
    public IB InterfaceB { get; set; }

    public ClassA()
    {
        // Call outside function to get Interface B
        IB interfaceB = Program.GetInsanceForIB();

        // Set IB to have A
        interfaceB.SetIA(this);
    }
}

[Serializable]
public class ClassB : IB
{
    public IA InterfaceA { get; set; }

    public void SetIA(IA value)
    {
        this.InterfaceA = value as ClassA;
    }
}

I get an error when I try too serialize because the 2 properties are interfaces. I want to serialize the properties.

How would I get around this?

I need to have references in each interface to the other. And I need to be able to serialize the class back and forth.

Answer 1

You have various bugs in your code, otherwise this would work just fine.

1. In the constructor for ClassA, your are setting an local variable IB, not the object's IB object.
2. In ClassB, you are casting back to the object concrete class, instead of leaving it alone as the interface type.

Here is what your code should look like:

public interface IA 
{ 
    IB InterfaceB { get; set; } 
}

public interface IB 
{ 
    IA InterfaceA { get; set; } 
    void SetIA(IA value);
}

[Serializable]
public class ClassA : IA
{    
    public IB InterfaceB { get; set; }    

    public ClassA()    
    {        
        // Call outside function to get Interface B        
        this.InterfaceB = new ClassB();

        // Set IB to have A        
        InterfaceB.SetIA(this);    
    }
}

[Serializable]
public class ClassB : IB
{    
    public IA InterfaceA { get; set; }    

    public void SetIA(IA value)    
    {       
        this.InterfaceA = value;    
    }
}

[STAThread]
static void Main()
{
    MemoryStream ms = new MemoryStream();
    BinaryFormatter bin = new BinaryFormatter();

    ClassA myA = new ClassA();

    bin.Serialize(ms, myA);

    ms.Position = 0;

    ClassA myOtherA = bin.Deserialize(ms) as ClassA;


    Console.ReadLine();
}