Contract to require a certain shared method

[Bryan]

I was trying to write an interface that would require the implementing
class to have a shared function, CanAdd() as boolean, which decides if
the current user can add a new instance of the particular class. This
authorization is at the class level, not the instance level, so it
should be shared, but I cannot find a way to require a class to
implement a shared method via an interface. Any suggestions?

[Cor Ligthert [MVP]]

Bryan,

Luckely you can AFAIK in VB not create mixed mode classes (some which need a
constructor and some which don't allow a constructer).

Legency this is in the C languages.

Cor
"Bryan" <br*******@gmail.comschreef in bericht
news:11**********************@e65g2000hsc.googlegr oups.com...

>I was trying to write an interface that would require the implementing
class to have a shared function, CanAdd() as boolean, which decides if
the current user can add a new instance of the particular class. This
authorization is at the class level, not the instance level, so it
should be shared, but I cannot find a way to require a class to
implement a shared method via an interface. Any suggestions?

[Herfried K. Wagner [MVP]]

"Cor Ligthert [MVP]" <no************@planet.nlschrieb:

Luckely you can AFAIK in VB not create mixed mode classes (some which need
a constructor and some which don't allow a constructer).

What's the relation to the OP's question?

Legency this is in the C languages.

At least not in C because C doesn't support classes at all.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Herfried K. Wagner [MVP]]

"Bryan" <br*******@gmail.comschrieb:

>I was trying to write an interface that would require the implementing
class to have a shared function, CanAdd() as boolean, which decides if
the current user can add a new instance of the particular class. This
authorization is at the class level, not the instance level, so it
should be shared, but I cannot find a way to require a class to
implement a shared method via an interface. Any suggestions?

That's simply not possible in VB (and in C# too). However, why not define a
base class containing the method? However, note that it's not possible to
override shared methods at all.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Cor Ligthert [MVP]]

">

What's the relation to the OP's question?

see your own kind of an echo, nothing wrong with in this case.

>Legency this is in the C languages.

At least not in C because C doesn't support classes at all.

C#

[Herfried K. Wagner [MVP]]

Cor,

"Cor Ligthert [MVP]" <no************@planet.nlschrieb:

>>Legency this is in the C languages.

At least not in C because C doesn't support classes at all.

C#

Even C# does not support static members implementing a member defined in an
interface.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Cor Ligthert [MVP]]

??

"Herfried K. Wagner [MVP]" <hi***************@gmx.atschreef in bericht
news:ui**************@TK2MSFTNGP03.phx.gbl...

Cor,

"Cor Ligthert [MVP]" <no************@planet.nlschrieb:

>>>Legency this is in the C languages.

At least not in C because C doesn't support classes at all.

C#

Even C# does not support static members implementing a member defined in
an interface.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Cor Ligthert [MVP]]

http://msdn2.microsoft.com/en-us/lib...s3(VS.80).aspx

Maybe is this answering what you are writing. This is not in VB.Net although
you can call in my idea the module a little like that.

Cor

"Herfried K. Wagner [MVP]" <hi***************@gmx.atschreef in bericht
news:ui**************@TK2MSFTNGP03.phx.gbl...

Cor,

"Cor Ligthert [MVP]" <no************@planet.nlschrieb:

>>>Legency this is in the C languages.

At least not in C because C doesn't support classes at all.

C#

Even C# does not support static members implementing a member defined in
an interface.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Herfried K. Wagner [MVP]]

"Cor Ligthert [MVP]" <no************@planet.nlschrieb:

http://msdn2.microsoft.com/en-us/lib...s3(VS.80).aspx

Maybe is this answering what you are writing. This is not in VB.Net
although you can call in my idea the module a little like that.

Behind the scenes modules and static classes share certain similarities, but
semantically they are different constructs used for different purposes.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Bryan]

That's simply not possible in VB (and in C# too). However, why not define a

base class containing the method? However, note that it's not possible to
override shared methods at all.

--
M S Herfried K. Wagner

I can't make the member part of a base class because it needs to
behave differently for each class. The method needs to be shared, and
I would just like to avoid any sort of late binding method calling.

[Herfried K. Wagner [MVP]]

"Bryan" <br*******@gmail.comschrieb:

>That's simply not possible in VB (and in C# too). However, why not define
a
base class containing the method? However, note that it's not possible
to
override shared methods at all.

I can't make the member part of a base class because it needs to
behave differently for each class. The method needs to be shared, and
I would just like to avoid any sort of late binding method calling.

Maybe you can utilize the Factory design pattern.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>