MonoTouch : How to serialize a type (like CLLocation) not marked as Serializable?

I'm working to an iPhone project using MonoTouch, and I need to serialize and save a simple object belonging to a c# class with a CLLocation type as data member:

[Serializable]
public class MyClass
{
    public MyClass (CLLocation gps_location, string location_name)
    {
        this.gps_location = gps_location;
        this.location_name = location_name;
    }

    public string location_name;
    public CLLocation gps_location;
}

This is my binary serialization method:

static void SaveAsBinaryFormat (开发者_运维问答object objGraph, string fileName)
    {
        BinaryFormatter binFormat = new BinaryFormatter ();
        using (Stream fStream = new FileStream (fileName, FileMode.Create, FileAccess.Write, FileShare.None)) {
            binFormat.Serialize (fStream, objGraph);
            fStream.Close ();
        }
    }

But when I execute this code (myObject is an instance of the above class):

try {
            SaveAsBinaryFormat (myObject, filePath);
            Console.WriteLine ("object Saved");
        } catch (Exception ex) {
            Console.WriteLine ("ERROR: " + ex.Message);
        }

I get this exception:

ERROR: Type MonoTouch.CoreLocation.CLLocation is not marked as Serializable.

Is there a way to serialize a class with CLLocation?

Since a class is not marked with the SerializableAttribute, it cannot be serialized. However, with a bit of extra work, you can store the information you need from it and serialize it, at the same time keeping it in your object.

You do this by creating a property for it, with the appropriate backing stores, depending on the information you want from it. For example, if I only want the coordinates of the CLLocation object, I would create the following:

[Serializable()]
public class MyObject
{

    private double longitude;
    private double latitude;
    [NonSerialized()] // this is needed for this field, so you won't get the exception
    private CLLocation pLocation; // this is for not having to create a new instance every time

    // properties are ok    
    public CLLocation Location
    {
        get
        {
            if (this.pLocation == null)
            {
                this.pLocation = new CLLocation(this.latitude, this.longitude);
            }
            return this.pLocation;

        } set
        {
            this.pLocation = null;
            this.longitude = value.Coordinate.Longitude;
            this.latitude = value.Coordinate.Latitude;
        }

    }
}

You can't add [Serializable] to MonoTouch types. Another alternative (to Dimitris excellent suggestion) is to use ISerializable on your own type.

That will give you total control on how to serialize the data from your type. You can also mix both approaches, use [Serializable] when possible or ISerializable otherwise inside your project.