Questions on __value class

  • Thread starter Thread starter Simon Cheng
  • Start date Start date
S

Simon Cheng

Hi,

In C#, value types are derived from System.ValueType (and hence from
System.Object).

Does this hold true for MC++?

__value class ValueClass {...};

Is ValueClass above derived from System::ValueType (and hence from
System::Object)?

Thanks,
Simon
 
Thanks, Jochen. The next question:

The derivation chain for ValueClass is:

System::Object
System::ValueType
ValueClass

Why objects derived from System::ValueType (_indirectly_ from
System::Object) are always allocated on stack, whereas objects derived
_directly_ from System::Object are always allocated on CLR heap? This means
if a value object calls a method inherited from System::Object but doesn't
override it, then the object needs to be boxed before the call can be made.
Is this just how it is designed?

Simon
 
Simon said:
The derivation chain for ValueClass is:

System::Object
System::ValueType
ValueClass

Why objects derived from System::ValueType (_indirectly_ from
System::Object) are always allocated on stack, whereas objects derived
_directly_ from System::Object are always allocated on CLR heap? This means
if a value object calls a method inherited from System::Object but doesn't
override it, then the object needs to be boxed before the call can be made.
Is this just how it is designed?
Click to expand...

That's pretty accurate. Here are a couple of articles that give some
background on value types:

CLR Design Choices
A Conversation with Anders Hejlsberg, Part VIII
Value Types
http://www.artima.com/intv/choices3.html

Value Types
http://blogs.msdn.com/cbrumme/archive/2003/05/10/51425.aspx
 
Back
Top