Tags: abstract, array, class, icloneable, icollection, ienumerable, ilist, inherits, net, public, sharp, specs, system, systemarray
System.Array inherits from IList ??
On .Net » .Net C# (C sharp)
6,481 words with 3 Comments; publish: Wed, 21 May 2008 23:53:00 GMT; (10078.13, « »)
Hi,
the specs for System.Array are :
public abstract class Array : ICloneable, IList, ICollection,
IEnumerable
but I can't use any of the functions presented by IList in my code
System.Array numbers = new int[5]{1,2,5,6,7};
numbers.Add(1) --> NOT POSSIBLE Compiler error : 'System.Array' does
not contain a definition for 'Add'
Array.Add(2) --> NOT POSSIBLE Compiler error : 'System.Array'
does not contain a definition for 'Add'
nor some belonging to ICollection : SyncRoot:yes, Count:no
numbers.Count --> NOT POSSIBLE
IEnumerable : no problem
What is reasoning behind all this ?
Already does intelisense not show those functions. But why not ? if the
specs make you suppose you could use them.
I thought maybe 'cause the functions are abstract so you must implement them
yourself (such as IList::Add) but then again , IEnumerable:GetEnumerator()
is an abstract function as well and I can use that one, no problem.
Thanks in advance
Chris
http://net-csharp.itags.org/q_dotnet-c-sharp_30422.html
All Comments
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- 3 Comments
- Chris,
If a class implements an interface, it doesn't have to expose those
members publically. In order to access the IList functionality on an array,
you must assign to an IList reference, like so:
// Get the IList.
IList pobjArray = new int[1]{1};
You can set pobjArray equal to any array reference.
Hope this helps.
- Nicholas Paldino [.NET/C# MVP]
- mvp.net-csharp.itags.org.spam.guard.caspershouse.com
"Chris" <christianc.net-csharp.itags.org.pandora.be> wrote in message
news:xT4xb.44779$kk1.1558594.net-csharp.itags.org.phobos.telenet-ops.be...
> Hi,
> the specs for System.Array are :
> public abstract class Array : ICloneable, IList, ICollection,
> IEnumerable
> but I can't use any of the functions presented by IList in my code
> System.Array numbers = new int[5]{1,2,5,6,7};
> numbers.Add(1) --> NOT POSSIBLE Compiler error : 'System.Array'
does
> not contain a definition for 'Add'
> Array.Add(2) --> NOT POSSIBLE Compiler error : 'System.Array'
> does not contain a definition for 'Add'
> nor some belonging to ICollection : SyncRoot:yes, Count:no
> numbers.Count --> NOT POSSIBLE
> IEnumerable : no problem
> What is reasoning behind all this ?
> Already does intelisense not show those functions. But why not ? if the
> specs make you suppose you could use them.
> I thought maybe 'cause the functions are abstract so you must implement
them
> yourself (such as IList::Add) but then again , IEnumerable:GetEnumerator()
> is an abstract function as well and I can use that one, no problem.
> Thanks in advance
> Chris
>
>
>
#1; Wed, 21 May 2008 23:54:00 GMT
- ah yes. of course !
Thnx for your quick response
"Nicholas Paldino [.NET/C# MVP]" <mvp.net-csharp.itags.org.spam.guard.caspershouse.com> wrote in
message news:eXHba6DtDHA.536.net-csharp.itags.org.tk2msftngp13.phx.gbl...
> Chris,
> If a class implements an interface, it doesn't have to expose those
> members publically. In order to access the IList functionality on an
array,
> you must assign to an IList reference, like so:
> // Get the IList.
> IList pobjArray = new int[1]{1};
> You can set pobjArray equal to any array reference.
> Hope this helps.
>
> --
> - Nicholas Paldino [.NET/C# MVP]
> - mvp.net-csharp.itags.org.spam.guard.caspershouse.com
> "Chris" <christianc.net-csharp.itags.org.pandora.be> wrote in message
> news:xT4xb.44779$kk1.1558594.net-csharp.itags.org.phobos.telenet-ops.be...
> > Hi,
> >
> > the specs for System.Array are :
> > public abstract class Array : ICloneable, IList, ICollection,
> > IEnumerable
> >
> > but I can't use any of the functions presented by IList in my code
> >
> > System.Array numbers = new int[5]{1,2,5,6,7};
> > numbers.Add(1) --> NOT POSSIBLE Compiler error : 'System.Array'
> does
> > not contain a definition for 'Add'
> > Array.Add(2) --> NOT POSSIBLE Compiler error :
'System.Array'
> > does not contain a definition for 'Add'
> >
> > nor some belonging to ICollection : SyncRoot:yes, Count:no
> > numbers.Count --> NOT POSSIBLE
> >
> > IEnumerable : no problem
> >
> > What is reasoning behind all this ?
> > Already does intelisense not show those functions. But why not ? if the
> > specs make you suppose you could use them.
> >
> > I thought maybe 'cause the functions are abstract so you must implement
> them
> > yourself (such as IList::Add) but then again ,
IEnumerable:GetEnumerator()
> > is an abstract function as well and I can use that one, no problem.
> >
> > Thanks in advance
> >
> > Chris
> >
> >
> >
> >
> >
>
#2; Wed, 21 May 2008 23:55:00 GMT
- "Chris" wrote...
> the specs for System.Array are :
> public abstract class Array : ICloneable,
> IList, ICollection,
> IEnumerable
> but I can't use any of the functions
> presented by IList in my code
> What is reasoning behind all this ?
An array is a special case of an IList, which have been handled based on the
fact that an array has a fixed size.
> I thought maybe 'cause the functions are abstract so
> you must implement them yourself (such as IList::Add) ...
It *is* implemented.
<quote>
Array.IList.Add
Implements IList.Add. Always throws NotSupportedException.
Array has a fixed size; therefore, elements cannot be added or removed. Use
SetValue to change the value of an existing element.
</quote>
You can read more in the documentation:
If the above link wraps, you can use this instead:
// Bjorn A
#3; Wed, 21 May 2008 23:56:00 GMT