Generics HowTo

  • Thread starter Thread starter Jacek Jurkowski
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Jacek Jurkowski

How to ensure that generic Collection
accept only String as a typeparam?
This causes an compiler error...

public class StringCollection<T> : List<T> where T : String

{

}
 
Jacek Jurkowski said:
How to ensure that generic Collection
accept only String as a typeparam?
This causes an compiler error...

public class StringCollection<T> : List<T> where T : String
{

}
Click to expand...

If you only want to be able to accept a single type as the type
parameter, it's not really generic any more. Just use:

public class StringCollection : List<string>
{
}
 
Dou You think I better derive from CollectionBase instead
of using generics? Why a cant use "where T : String"?
If you only want to be able to accept a single type as the type
parameter, it's not really generic any more. Just use:

public class StringCollection : List<string>
{
}
Click to expand...

Its still possible: StringCollection<int> = new StringCollection<int>();
 
Jacek Jurkowski said:
Dou You think I better derive from CollectionBase instead
of using generics? Why a cant use "where T : String"?


Its still possible: StringCollection<int> = new StringCollection<int>();
Click to expand...

It shouldn't be, since StringCollection has no generic type. You don't want

public class StringCollection<T> : List<string> { };

you want
public class StringCollection : List<string> { };

You might want to look into the Collection<T> class as well if you need more
flexibility than List<T> offers.
 
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