reflection question

[Antony]

Hello - I am wanting to print out a "Yes" next to classes that
implement "Interface0 1", otherwise a "No". Here is my code. It crashes
with a null reference exception and I am not sure why. Ideas?
Thank you for you help.
Tony
Imports System.Reflecti on

Public Class Form1
Inherits System.Windows. Forms.Form

''Windows Form Designer generated code

Interface Interface01
End Interface

MustInherit Class Abstract01
End Class

Class Class01
Implements Interface01
End Class

Class Class02
End Class

Class Class03
Inherits Class01
End Class

Class ClassA2
Inherits Abstract01
End Class

Private Sub Button1_Click(B yVal sender As System.Object, _
ByVal e As System.EventArg s) Handles Button1.Click
Dim asmbly As [Assembly] = [Assembly].GetExecutingAs sembly()
Dim asmblyType As Type
For Each asmblyType In asmbly.GetTypes
If asmblyType.Base Type.Equals(Get Type(Interface0 1)) Then
Debug.Write("Ye s: ")
Else : Debug.Write("No : ")
End If
Debug.WriteLine (asmblyType.Ful lName)
Next
End Sub
End Class

[Fergus Cooney]

Hi Tom,

Maybe I should have said 'executable' or 'application' then, for it is the
collection of Assemblies that make up a program that I'm thinking about.

Regards,
Fergus

[Fergus Cooney]

Hi Tony,

Lol, actually this is out of my area but I was asking on your behalf as I
knew that this was what you were after. :-)

Having just seen Tom's answer, I wanted to get in there quick and steer
him right. I do this quite often (in the group generally - not with Tom). This
time I chose to do it as a question but my arrow fell short. :-((

I think the problem with GetAssemblies is that it will get those that have
been loaded so far, not the entire list. I would hope that there's a way to
get them all. It makes good sense that the information is there somewhere but
it may be distributed rather than centralised.

What do you reckon Tom? ;-)

Regards,
Fergus

[CJ Taylor]

"Fergus Cooney" <fi******@tesco .net> wrote in message
news:ur******** *****@TK2MSFTNG P11.phx.gbl...

Hi Tony,

Lol, actually this is out of my area but I was asking on your behalf as I knew that this was what you were after. :-)

Having just seen Tom's answer, I wanted to get in there quick and steer him right. I do this quite often (in the group generally - not with Tom). This time I chose to do it as a question but my arrow fell short. :-((

I think the problem with GetAssemblies is that it will get those that have been loaded so far, not the entire list. I would hope that there's a way to get them all. It makes good sense that the information is there somewhere but it may be distributed rather than centralised.

Well, might as well through my hat into the ring as I've recently worked
with reflection.

Now, regarding the first question of a collection of the assemblies that
make up an "applicatio n" being stored somewhere, Tom's answer is dead on.
Or at least I think the best way to accomplish the task with the way most
people program. That is, you have a primary executable which may call a
series of libraries held in other assemblies. These are all usually loaded
at executation of the main assembly. The only time its not, is if your
doing something like modular coding where you use reflection to dynmiaclly
load assemblies at different times in the programs lifecycle.

If that is true, you could always recusivly push through each reference of
the primary assembly. Use GetReferencedAs semblies and
GetSatelliteAss emblies (if needed). Which both return collections of
assembly references. So, unless you are dynamically invoking methods your
program knows absolutly nothing about from assemblies it knows absolutly
nothing about, (I mean no interfaces either, kinda like a really really
really dynamic unit tester... hmmmmm.. interesting idea). there should be
no need other than those two methods. And as said, going through them
recursivly will tell you every single assembly you want to know about.

Hope it helps, keep the peace, and keep on rockin in the freeworld ted
nugent style.

-CJ
What do you reckon Tom? ;-)

Regards,
Fergus