To interface or not to interface

[Steven Schveighoffer]

On Tue, 25 May 2010 02:26:02 -0400, Kagamin <spam at here.lot> wrote:

> Recently I've hit a problem with collections in C#. Given classes
> class A {}
> class B {}
> And two collections Collection<A> and Collection<B> it's possible to  
> concat them into an array A[]. The efficient way to do it is to use  
> CopyTo(T[],int) method, but it accepts only array of exact collection  
> item's type, so I had to change the Collection<B> type to Collection<A>.

Did you mean

class B : A {} ?

According to this page, it says that an exception could be thrown if "Type  
T cannot be cast automatically to the type of the destination array."   
This implies that a destination array type to which T could automatically  
be cast should work.

http://msdn.microsoft.com/en-us/library/0efx51xw%28v=VS.100%29.aspx

But the larger point that compile-time code generation can help with this  
is valid.

-Steve