Thread: How to retrieve an object's address?

Hi,

is there a way to retrieve the address of an object? (Or some id that is unique to the object)

I want to define the identity of an Edge based on the addresses of the Nodes it refers to.
But because GetHashCode doesnt guarantee uniqueness, this solution is unsafe:

Code:

   public int CompareTo(Edge other)
            {
 	            int result = from.GetHashCode() - other.from.GetHashCode();
                if(result != 0)
                    return result;

                return to.GetHashCode() - other.to.GetHashCode();
            }

MSDN online or MSDN Express Edition.

There are two ways of getting an id for and object and the hash method is a generic method and the one that I had seen most frequently used. There is another that is quite similar to the methods utilized in C++ to get an objects signature, but I can't recall the way of going about to get it. I have seen references to the method in the MSDN Express edition and I personally recommend getting it (MSDN Express Ed.) if you do not have it already.

A couple possible leads that might get you started are: comparing objects through equality, dynamically creating and/or destroying objects, and look up .Net assembly files and IL Dasm to access your assemblies to search for object ID references.

A really good book I am reading right now that addresses these types of Intermediate to Advanced Professional Programming level topics is Pro C# 2008, and the .Net 3.5 Platform published by Apress Books. Excellent author and seriously deep treatment of C# and the .Net Framework from a hacker oriented/reverse engineering point of view geared toward getting a certification.

I had this exact problem once.

The short answer is you can but it wouldn't work. C# allows objects to be moved around in memory, so the same actual object might occupy different memory locations at different times.

My own method was to simply count nodes:

Code:

public class Node {

      private static int mCount = 0;

      private int ID;

      public Node()
      {
            ID = Interlocked.Increment(mCount);
      }

The Interlocked.Increment in place of just "++mCount" is for thread safety.

This one obviously doesn't reuse old IDs, and it has a hard limit of 2^32 possible ID values before you wrap all the way back to ID #1 again. That wasn't an issue for me, maybe it won't matter for you either.