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| Interface static member ? |
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This message was discovered on microsoft.public.dotnet.languages.csharp.
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| TruongLapVi |
Hi,
Why C# does not support Interface static member ?
Some time I want implement NullObject Pattern:
public interface INullObject {
public static INullObject Null {
get { return NullObject.Instance; } // !!! Wrong, C# not support ?
}
}
public class NullObject {
private static instance; // Singleton pattern
private NullObject () {};
static NullObject() { instance = new NullObject; }
public static NullObject Null {
get { instance; )
}
}
}
public class NullObjectImpl : INullObject, FooClass {
...........
}
--
Vi
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| Frank Oquendo |
TruongLapVi wrote:
[Original message clipped]
A static membre belongs to a particular class. An interface is not a class.
Even so, interfaces are not allowed to have method definitions. That's an
implementation detail.
--
There are 10 kinds of people. Those who understand binary and those who
don't.
http://code.acadx.com
(Pull the pin to reply)
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| TruongLapVi |
> A static membre belongs to a particular class. An interface is not a
class.
[Original message clipped]
I think that static member is not instance member, ie we needn't creat new
instance for calling static member, so I expect that C# should support this
feature.
Thank for your answer.
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| Vadym Stetsyak |
"TruongLapVi" <Click here to reveal e-mail address> wrote in message
news:e3#Click here to reveal e-mail address...
[Original message clipped]
interface is a class declared as abstract class and all the methods defined
in it are also abstract.
Interfaces define mereley methods and classes that implement interfaces must
implement those methods.
[Original message clipped]
it supports this feature but not with interfaces.
Interfaces may only contain signatures for methods, properties, indexers and
events
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| dilipdotnet at apdiya.com |
Hello Vi,
Interface only describes behaviour and serves the purpose of describing
a contractual obligation for classes implementing the interface that
certain behaviour is implemented.
The .net framework is not capable of downcasting objects to their
interfaces. If for example object A implements interface I1 and I2 the
framework will not be able to intelligently downcast the object to I1 or
I2. whereas if an abstract class is used there is no issue as there is
no multiple inheritence.
Hope that makes more sense than its confusing
Thanks
TruongLapVi wrote:
[Original message clipped]
--
Regards,
Dilip Krishnan
MCAD, MCSD.net
dilipdotnet at apdiya dot com
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