How to get Object size in memory

There is cache(a queue object) in my application.now,I want to know how much space in memory is being taken up by that object at runtime.

Marshal.SizeOf(...) Is it realy size of object in memory

Visual C#9

No, Marshal.Sizeof() is the amount of memory required to marshal an object to/from native code. The size of any given object is undefined and cannot truly be determined in .NET. outside of a debugger. http://channel9.msdn.com/ShowPost.aspx PostID=231084 has a thread discussing similar.