writing object to a file

I am trying to save data object to a file. I followed the example http://tech.pro/tutorial/618/csharp-tutorial-serialize-objects-to-a-file

And it is working well on window and android device. When I try to run it on iPhone or iPad it is giving error.

I think the error due to BinaryFormatter

Can anyone give some help on proper way to do this?

I think the problem comes from the List in the object. If I don’t have any list all get saved properly. Any idea how to solve this?

The example in the link has following code

[Serializable()]
public class NameSeriClas : ISerializable
{
    List<NameClas> nameClasList;

    public List<NameClas> NameClasList
    {
        set
        {
            this.nameClasList = value;

        }
        get
        {
            return this.nameClasList;
        }
    }
    public NameSeriClas()
    {
    }
    public NameSeriClas(SerializationInfo info, StreamingContext cxtx)
    {
        this.nameClasList = (List<NameClas>)info.GetValue("NameClasList", typeof(List<NameClas>));
    }
    public void GetObjectData(SerializationInfo info, StreamingContext cxtx)
    {
        info.AddValue("NameClasList", this.nameClasList);
    }
}