Hi Jon Hyland,

The only way I can think of is using Marshal.SizeOf(object).

Just a point to note - Marshal.SizeOf will return the unmanaged size of the
object. The runtime adds overhead for each type so the managed size would be
slightly different.

That said, here's an excellent article in the december issue of the MSDN
magazine on memory usage and optimazations:
http://msdn.microsoft.com/msdnmag/issues/05/01/MemoryOptimization/default.aspx

According to the article, you could use performance counters and measure the
change in the heap memory when creating your objects to get a feel of the
size your objects are occupying. Also, you could use the CLR profiler (link
in the article for the download) to monitor memory usage.

hope that helps..
Imran.

I have had excellent results using .NET Memory Profiler. I believe they have
a free trial.