nested structs marshalled to Bytes: Errors.

Unity Engine
1

Hello,
I have 2 structs:

public struct th_skimFacadeSolution{
    public transportTypes sType;
    public th_VMPObjGeneric[] allparts;

    public th_skimFacadeSolution(th_VMPObjGeneric[] allcomps, bool velocity) {
        allparts = allcomps;
        sType = velocity ? transportTypes.skimVelocity : transportTypes.skimPositions;
    }
}

public struct th_VMPObjGeneric {
    public string sName;
    public Vector3 sPos;
    public Vector3 sRot;

    public th_VMPObjGeneric(string n,Vector3 p,Vector3 r) {
        sName = n;
        sPos = p;
        sRot = r;
    }
}

I then have a converter class for the first to byte[ ] and back:

 public static byte[] skimSolutionConverter(th_skimFacadeSolution str) {
        int size = Marshal.SizeOf(str);
        byte[] arr = new byte[size];
        IntPtr ptr = Marshal.AllocHGlobal(size);
        Marshal.StructureToPtr(str,ptr,true);
        Marshal.Copy(ptr,arr,0,size);
        Marshal.FreeHGlobal(ptr);
        arr = addByteToArray(arr,(byte)str.sType);
        return arr;
    }

    public static th_skimFacadeSolution skimSolutionConverter(byte[] bytes) {
        bytes = removeFirstByte(bytes);
        th_skimFacadeSolution str = new th_skimFacadeSolution();
        int size = Marshal.SizeOf(str);
        IntPtr ptr = Marshal.AllocHGlobal(size);
        Marshal.Copy(bytes,0,ptr,size);
        str = (th_skimFacadeSolution)Marshal.PtrToStructure(ptr,str.GetType());
        Marshal.FreeHGlobal(ptr);
        return str;
    }

I then get this error on receiving the bytes and converting:

 MarshalDirectiveException: Structure field of type th_VMPObjGeneric[] can't be marshalled as LPArray (wrapper unknown) th_skimFacadeSolution:PtrToStructure (intptr,object)  }

I get that Marshalling cant deal with the nested struct array inside the first struct as it is currently written. I have tried to go over the documents, but this is well outside my wheelhouse.

Is this a simple fix, or does it involve a lot more research on my behalf?

Thanks very much,
Ryan

2

and for added details:
allparts[ ].length is unknown at time of creation.

3

This has been solved.