Generics Syntax help

[Guest]

Anyone know if you can have an OR type of contraint in the where clause?

Psudo example
Void MyMethod<T>(T list, string b) where T:interface1 OR interface2 {}

Does that make sense? ( T should implement at least one of the interfaces (
interface1 and/or interface2 )

 

[Nicholas Paldino [.NET/C# MVP]]

AdamH,

No such constraint exists. The constraints are all and operations,
meaning each one has to apply.

Hope this helps.

 

[Guest]

Suspected that to be the truth, guess I was hoping otherwise ( or at least
for a cheat )
..
I’ve been wrong so many times before……..
Thx just the same

AdamH,

No such constraint exists. The constraints are all and operations,
meaning each one has to apply.

Hope this helps.


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

Anyone know if you can have an OR type of contraint in the where clause?

Psudo example
Void MyMethod<T>(T list, string b) where T:interface1 OR interface2 {}

Does that make sense? ( T should implement at least one of the interfaces
(
interface1 and/or interface2 )

 

[Marc Gravell]

Well, from your example it isn't 100% clear what you are doing with T, but
is it possible you could do this with straight overloading?

i.e.

void MyMethod(ISomeInterface1 list, string b)
void MyMethod(ISomeInterface2 list, string b)

Which could then perhaps call down to some private function that will use
either?

Marc

 

[Robbe Morris [C# MVP]]

I can't find any mention of this functionality in the docs
as I read them. You can specify more than one
interface contract per generic type but the docs
appear to infer that both constraints would be
required and not in the form of an OR clause.

 

[Jon Skeet [C# MVP]]

I can't find any mention of this functionality in the docs
as I read them. You can specify more than one
interface contract per generic type but the docs
appear to infer that both constraints would be
required and not in the form of an OR clause.

Indeed - and even if it *were* available, I can't see how it would be
useful. You'd have to keep checking which interface was implemented in
order to use it.

 

[Robbe Morris [C# MVP]]

Yep, I guess I couldn't see a design reason to do
this either. Some sort of factory pattern "may be"
the route to go or some scheme of method overloads
perhaps.

--
Robbe Morris - 2004-2006 Microsoft MVP C#
http://www.eggheadcafe.com/forums/merit.asp