I can't answer that for him, but I would assume that is what he wants
otherwise he wouldn't want to use statics.
My best guess would be that he is plans on wanting statics which are
shared between different base types i.e.
class GenericVehicleBase<T>
{
public static int CategoryId;
public Engine EngineType;
}
class CarBase
{
public int Doors;
public bool SunRoof;
}
class TruckBase
{
public int Doors;
public bool SunRoof;
public bool FourWheelDrive;
}
class BoatBase
{
public bool InboardMotor;
}
class Car : GenericVehicleBase<CarBase>
{
// All cars are of Category 1.
CategoryId = 1;
}
class Truck : GenericVehicleBase<TruckBase>
{
// All trucks are of Category 2.
CategoryId = 2;
}
class Boat : GenericVehicleBase<BoatBase>
{
// All boats are of category 3.
CategoryId = 3;
}
Would make more sense if they were actually assigned elsewhere, perhaps
after its creation, for custom data. Perhaps, using the above example,
this software is used by various vehicle maintenance shops, and each one
uses a different numbering system for their vehicle categories. Having
the variable static, but static to a particular generic type would make
it somewhat more flexible. Obviously there are other ways to do this,
but this was just a simple example of how it could be used.
-----Original Message-----
From: Discussion of advanced .NET topics.
[mailto:[EMAIL PROTECTED] On Behalf Of Peter Ritchie
Sent: Monday, February 20, 2006 09:01
To: [email protected]
Subject: Re: Statics on Generic classes
Are you OK with the following:?
class GenericBase<T>
{
public static int x;
}
class GenericClass1 : GenericBase<int>
{
}
class GenericClass2 : GenericBase<decimal> { }
class GenericClass3: GenericBase<int>
{
}
//...
GenericClass1.x = 5;
GenericClass2.x = 10;
GenericClass3.x = 15;
String text;
text.Format("{0} {1} {2}", new object[] {GenericClass1.x,
GenericClass2.x, GenericClass3.x}); Debug.WriteLine(text);
//eof
...which would output "15 10 15" not "5 10 15"?
On Mon, 20 Feb 2006 17:30:04 +1300, Dean Cleaver
<[EMAIL PROTECTED]> wrote:
>Peter,
>
>Actually, now that you mention it I will see what I want. Basically, in
>almost every class I have I have 2 static datasets containing a list of
>all of the items in the database for that class - especially the likes
>of a "Country" table where countries are not added regularly if ever, I
>keep an in-memory copy of them for quick population of a combo box for
>example. Saves on round-tripping to the db when on a VPN from a remote
>office.
>
>So what I would be doing is GenericBase<x> and then GenericBase<y> etc
>where every class will have a different generic type, which from what
>you are saying will in fact give me my desired results, and a quick
>test has proven that:
>
>
>class GenericBase<T>
>{
> public static int x;
>}
>
>class GenericClass1 : GenericBase<int>
>{
>}
>
>class GenericClass2 : GenericBase<decimal> { }
>
>And then ran this:
>
>GenericClass1.x = 5;
>GenericClass2.x = 10;
>MessageBox.Show(GenericClass1.x.ToString());
>
>Returns 5 - meaning that I can define a Generic Base with static
>members, and then define 150 classes from that each based on a
>different type, and I will in effect have 150 individual sets of static
>members, not 1 static member like I would have had with a normal
>non-generic base class. I just made the mistake of creating 2 classes
>of GenericBase<int>, which will share the static members.
>
>Much appreciated - I'd been looking at the code trying all sorts, but
>never thought to change the type.
>
>Cheers,
>Dino
>
>-----Original Message-----
>From: Discussion of advanced .NET topics.
>[mailto:[EMAIL PROTECTED] On Behalf Of Peter Ritchie
>Sent: Monday, 20 February 2006 16:54
>To: [email protected]
>Subject: Re: [ADVANCED-DOTNET] Statics on Generic classes
>
>Statics in generics don't operate any differently than non-generic
>classes. They're basically globals that are scoped within a class.
>
>Generics are also not like unmanaged C++ templates; their body is not
>copied (inlined) for each use.
>
>In your example, x is a member of GenericBase<int>. If you changed
>your declaration of GenericClass2 to derive from GenericBase<Decimal>
>(or any other type except int) then you'd see the results you expected,
>but not what you want.
>
>If you're expecting a class declaration deriving from a generic to
>operate like an instance (i.e. each class declaration have its own copy
>of derived
>statics) then you're out of luck.
>
>What were you hoping to accomplish? In case there's another way of
>doing what you want.
>
>On Mon, 20 Feb 2006 15:43:36 +1300, Dean Cleaver
><[EMAIL PROTECTED]> wrote:
>
>>I just tried a test like this:
>>
>>class GenericBase<T>
>>{
>> public static int x;
>>}
>>
>>class GenericClass1 : GenericBase<int> { }
>>
>>class GenericClass2 : GenericBase<int> { }
>>
>>And then ran this:
>>
>>GenericClass1.x = 5;
>>GenericClass2.x = 10;
>>MessageBox.Show(GenericClass1.x.ToString());
>>
>>To my disappointment, it displayed 10 not 5 as I had hoped - basically
>>means that any statics on a Generic base are common to all derivations
>>of that Generic class, not to each derived class - or is there another
>>way to effect what I am trying to do?
>
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