Specialization of generics

[Adam Badura]

Is there a way to specialize generic types or methods tha same way as it
is possible in C++ for example?
I know that instead of specializing a class

class MyCollection<TType>

for string type I could do something like

class MyStringCollection : MyCollection<string>

or even something like

class MyCollection<Type> : IMyCollection<Type>
class MyStringCollection : IMyCollection<string>

However selection of type MyStringCollection is not automatic. If
programer uses MyCollection<string> (perhaph unaware of the existance of
specialized class) then nothing will even let him know that he should use
MyStringCollection.

So to sum up is there a way in C# to do it like you can do it in C++?

Adam Badura

 

[Guest]

you could use the 'ObsoleteAttribute' but it could be percieved as misleading

check out:

http://msdn2.microsoft.com/en-us/library/aa664623(VS.71).aspx

HTH

Ollie Riches

 

[Adam Badura]

you could use the 'ObsoleteAttribute' but it could be percieved as

misleading

But if the generic class is marked with this attribute then warning will
be issued even if programer uses MyCollection<int> for which there is no
specialization and the generic schould be used. So indeed misleading.

Adam Badura

 

[Allan Ebdrup]

Is there a way to specialize generic types or methods tha same way as
it is possible in C++ for example?
I know that instead of specializing a class

class MyCollection<TType>

for string type I could do something like

class MyStringCollection : MyCollection<string>

or even something like

class MyCollection<Type> : IMyCollection<Type>
class MyStringCollection : IMyCollection<string>

However selection of type MyStringCollection is not automatic. If
programer uses MyCollection<string> (perhaph unaware of the existance of
specialized class) then nothing will even let him know that he should use
MyStringCollection.

So to sum up is there a way in C# to do it like you can do it in C++?

It's not the prettiest solution but you could check if the type of the
generic parameter is a string and check that this.GetType() is
MyStringCollection or not MyCollection<string>, and throw an descriptive
error if it is. In the constructor.
Of corse you only get runtime checking, and it's not encapsuled very well.

Kind Regards,
Allan Ebdrup

 

[Adam Badura]

It's not the prettiest solution but you could check if the type of the

generic parameter is a string and check that this.GetType() is
MyStringCollection or not MyCollection<string>, and throw an descriptive
error if it is. In the constructor.
Of corse you only get runtime checking, and it's not encapsuled very well.

Yes. I thought on that also. But to be honest I think it is better to
not check it at all if the check should look like this. However this could
be improved if this check was done as Debnug.Assert to not cause errors in
the Release version. After all the reason to do specialization is most often
to do some optimizations not to correct errors, co using unspecialzied
version in moste cases is not required - only causes worse perfomance.

Adam Badura

 

[Adam Badura]

you could use the 'ObsoleteAttribute' but it could be percieved as

misleading

Giving it second thoughts I think that perhaps it is possible to make
own attribute which will do the nessecery checkings and issue a warning when
required.

But still this is kind of workaround. The best solution - in my
opinion - is to have the effect like in C++. If programmer writes
MyCollection<string> then compiler selectes specialized implementation
instead of the generic one.

Adam Badura

 

[Ben Voigt [C++ MVP]]

Is there a way to specialize generic types or methods tha same way as
it is possible in C++ for example?

No, there is not.