List of a generic type

[Jorge Varas]

Hi all,

Is it possible to have a collection of a generic type?

for example:

class a<twhere t : class, new
{
}

class b
{
List<a<t>p;
}

I know that the previous example does not work, but any ideas on how to make
that concept work?

I need a collection that stores objects that are of a generic type.

Jorge Varas

[Dustin Campbell]

Is it possible to have a collection of a generic type?

>
for example:

class a<twhere t : class, new
{
}
class b
{
List<a<t>p;
}

I know that the previous example does not work, but any ideas on how
to make that concept work?

I need a collection that stores objects that are of a generic type.

Sure, you can do that by defining the same generic parameter on class b:

class a<twhere t : class, new()
{
}
class b<twhere t : class, new()
{
List<a<t>p;
}

Best Regards,
Dustin Campbell
Developer Express Inc.

[Jorge Varas]

Sorry, my bad, I didn't explained the problem with enough detail.

class a<twhere t: class, new
{
void DoSomething()
{
}
}

class b<uwhere u: class, new
{
List<a<v>list;

void setup()
{
if (typeof(u).Full Name == "xxx")
{
list.Add(new a<int>());
list.Add(new a<string>());
}
}

void Cascade()
{
foreach(a<titem in list)
item.DoSomethin g();
}
}

So u and v are different types, the fact that b is instanciated with a type t1 does not define that the list is going to be of type a<t1>. Actually, the list might contain instantiations of 'a' with different types under different cases

BTW. I know that the previous example does not work... but it ilustrate the problem that I have.

"Dustin Campbell" <du*****@no-spam-pleasedevexpres s.comwrote in message news:c1******** *************** ***@news.micros oft.com...

>Is it possible to have a collection of a generic type?

for example:

class a<twhere t : class, new
{
}
class b
{
List<a<t>p;
}

I know that the previous example does not work, but any ideas on how
to make that concept work?

I need a collection that stores objects that are of a generic type.

Sure, you can do that by defining the same generic parameter on class b:

class a<twhere t : class, new()
{
}
class b<twhere t : class, new()
{
List<a<t>p;
}

Best Regards,
Dustin Campbell
Developer Express Inc.

[Dustin Campbell]

Sorry, my bad, I didn't explained the problem with enough detail.

>
class a<twhere t: class, new
{
void DoSomething()
{
}
}
class b<uwhere u: class, new
{
List<a<v>list;
void setup()
{
if (typeof(u).Full Name == "xxx")
{
list.Add(new a<int>());
list.Add(new a<string>());
}
}
void Cascade()
{
foreach(a<titem in list)
item.DoSomethin g();
}
}
So u and v are different types, the fact that b is instanciated with a
type t1 does not define that the list is going to be of type a<t1>.
Actually, the list might contain instantiations of 'a' with different
types under different cases

BTW. I know that the previous example does not work... but it
ilustrate the problem that I have.

So, if I understand correctly, you want to be able to use a generic type
without actually closing it. E.g., like this:

class b<uwhere u: class, new()
{
List<a<>list;
}

Correct? If so, you can't do that with C#.

Best Regards,
Dustin Campbell
Developer Express Inc.

[Jorge Varas]

I can do it using objects and the checking if the type of the object was
constructed from the generic class a, but I hoped for a more elegant
solution.

Thanks for your clarification.

"Dustin Campbell" <du*****@no-spam-pleasedevexpres s.comwrote in message
news:c1******** *************** ***@news.micros oft.com...

>Sorry, my bad, I didn't explained the problem with enough detail.

class a<twhere t: class, new
{
void DoSomething()
{
}
}
class b<uwhere u: class, new
{
List<a<v>lis t;
void setup()
{
if (typeof(u).Full Name == "xxx")
{
list.Add(new a<int>());
list.Add(new a<string>());
}
}
void Cascade()
{
foreach(a<tite m in list)
item.DoSomethi ng();
}
}
So u and v are different types, the fact that b is instanciated with a
type t1 does not define that the list is going to be of type a<t1>.
Actually, the list might contain instantiations of 'a' with different
types under different cases

BTW. I know that the previous example does not work... but it
ilustrate the problem that I have.

So, if I understand correctly, you want to be able to use a generic type
without actually closing it. E.g., like this:

class b<uwhere u: class, new()
{
List<a<>list;
}

Correct? If so, you can't do that with C#.

Best Regards,
Dustin Campbell
Developer Express Inc.

[Joanna Carter [TeamB]]

"Dustin Campbell" <du*****@no-spam-pleasedevexpres s.coma écrit dans le
message de news: c1************* *************@n ews.microsoft.c om...

| Correct? If so, you can't do that with C#.

....unless you insert a non-generic base class before the generic one.

class b
{
}

class b<T: b
{
}

then you can have a List<b>, but you will have to determine what types the
items really are before you deal with them.

Joanna

--
Joanna Carter [TeamB]
Consultant Software Engineer

[Jorge Varas]

..Thanks! this works for my situation

public abstract class lc {
public abstract void Cascade();
}

public class lvc<T: lc where T : class, new() {
public override void Cascade() {
}
}

public class a {

List<lclist;

void SetUp() {
list.Add(new lvc<int>());
list.Add(new lvc<string>());
}

public void DoSomething() {
foreach(lc item in list)
item.Cascade();
}
}

I added the full solution so it is left in the archive... it bothers me to be looking for a solution to a problem just to find a posting saying "Thanks!, I solved" and nothing more...
"Joanna Carter [TeamB]" <jo****@not.for .spamwrote in message news:Oz******** ******@TK2MSFTN GP02.phx.gbl...

"Dustin Campbell" <du*****@no-spam-pleasedevexpres s.coma écrit dans le
message de news: c1************* *************@n ews.microsoft.c om...

| Correct? If so, you can't do that with C#.

...unless you insert a non-generic base class before the generic one.

class b
{
}

class b<T: b
{
}

then you can have a List<b>, but you will have to determine what types the
items really are before you deal with them.

Joanna

--
Joanna Carter [TeamB]
Consultant Software Engineer