Conversion from void* to object in C#

Question

Hello,

In a C# project, I need to pass object parameters by putting references in a structure. i.e. I have a structure passed to a dispatcher

struct SOMESTRUCT
{
    public int lpObject;
}

Where lpObject holds a pointer to a custom object like

class SomeClass
{
    private string foo;
}

And the SOMESTRUCT structure is passed from method to method to finally reach my code. I cannot modify the execution flow nor the strange SOMSTRUCT system, so I guessed the only solution was to cast my object to a pointer like this :

var myObject = new SomeClass();
GCHandle GC = GCHandle.Alloc(myObject, GCHandleType.Pinned);
int myRef = GC.AddrOfPinnedObject().ToInt32();
GC.Free();

SOMESTRUCT struct;
struct.lpObject = myRef;
someMethod(struct);

However, I can't figure out how to retrieve the myObject members from the lpObject fields. Something like this:

SomeClass myObject = CastPointerToObject(struct.myRef) as SomeClass;

Is there a way to do it, or is it impossible ? How can I tell the garbage collector to handle the object ? Should I create a new Garbage-collected object and copy the data field by field ?

TYIA,

Answer 1

Do you mean you want to cast the returned pointer back to a struct?

Similar to:

lvHitTestInfo = (LVHITTESTINFO)Marshal.PtrToStructure(lP, typeof(LVHITTESTINFO));

Where lvHitTestInfo is a structure and lp a pointer.

Or i didn't understand your question properly. Maybe you can explain more (more complete code sample).