Use a System.Type in Generics?

06-05-06, 07:33 PM

cmay

Is this something you are not allowed to do?

I basically want to create an instance of a generic class where the
type T is not know at compile time.

e.g.

dim s as System.Type = GetMyType()
dim o as MyObj(Of s)

I have not found a way to do this, so I am guessing it is not possible.

06-05-06, 08:24 PM

Herfried K. Wagner [MVP]

"cmay" <cmay> schrieb:
> I basically want to create an instance of a generic class where the
> type T is not know at compile time.
>
> e.g.
>
> dim s as System.Type = GetMyType()
> dim o as MyObj(Of s)

\\\
Dim GenericType As Type = GetType(List(Of ))
Dim ParameterTypes() As Type = {GetType(Integer)}
Dim o As Object = _
Activator.CreateInstance( _
GenericType.MakeGenericType(ParameterTypes) _
)
///

06-05-06, 09:00 PM

cmay

Thanks HKW!

Herfried K. Wagner [MVP] wrote:
[..]

06-06-06, 06:50 AM

Cor Ligthert [MVP]

Herfried,

I am curious how I can use this Generic List of a typed class, while I don't
know the members of the class?

Can you give me an example?

Cor

"Herfried K. Wagner [MVP]" <hirf-spam-me-here> schreef in bericht
news:1208
[..]

06-06-06, 11:36 AM

Herfried K. Wagner [MVP]

"Cor Ligthert [MVP]" <notmyfirstname> schrieb:
> I am curious how I can use this Generic List of a typed class, while I
> don't know the members of the class?

The problem is that you can only do that using reflection because 'List(Of
X)' is not a 'List(Of )'. Thus I do not think that the solution I posted
makes much sense because generics are mainly a compile-time feature and the
compile-time advantages are lost when using reflection.

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