Hi,

how can I create an instance (object) of a class (form) if I only know the
classname (VB.NET 1.0)?
I need to do this in a complex app where jobs consist of parts. Each part's
data is saved in a separate database table. For the parts, the form's class
name is saved in a data table, so that I know which form to use. As this is
a string, I need to be able to create the form by it's name (like
CreateObject() does for COM objects).

--
Any help gladly appreciated!

Rene Mansveld
Spider IT - Germany
www.Spider-IT.de / www.Spider-IT.net

Please reply to the newsgroup(s) )

take a look at the Activator.CreateInstance method in the System.Reflection
namespace.

hope that helps..
Imran.

"Rene Mansveld" <(E-Mail Removed)> wrote in message
news:%(E-Mail Removed)...
> Hi,
>
> how can I create an instance (object) of a class (form) if I only know the
> classname (VB.NET 1.0)?
> I need to do this in a complex app where jobs consist of parts. Each
> part's
> data is saved in a separate database table. For the parts, the form's
> class
> name is saved in a data table, so that I know which form to use. As this
> is
> a string, I need to be able to create the form by it's name (like
> CreateObject() does for COM objects).
>
> --
> Any help gladly appreciated!
>
> Rene Mansveld
> Spider IT - Germany
> www.Spider-IT.de / www.Spider-IT.net
>
> Please reply to the newsgroup(s) )
>
>

Thanks for the quick answer!

Unfortunately I couldn't get this to work, and according to the help, this
will create an instance of a Type.
I tried the Activator.CreateInstance(Nothing, "Auftrag") call, but I got
this exception:
A non handled exception of type 'System.TypeLoadException' occured in
mscorlib.dll.
Extra info: The type Auftrag in the assembly ..., Version=0.3.1783.15723,
Culture=neutral, PublicKeyToken=null could not be loaded.
(translated from german)

Any ideas anyone?

--
Rene Mansveld
Spider IT - Germany
www.Spider-IT.de / www.Spider-IT.net

Please reply to the newsgroup(s) )

"Imran Koradia" <(E-Mail Removed)> schrieb im Newsbeitrag
news:(E-Mail Removed)...
> take a look at the Activator.CreateInstance method in the
System.Reflection
> namespace.
>
> hope that helps..
> Imran.
>
> "Rene Mansveld" <(E-Mail Removed)> wrote in message
> news:%(E-Mail Removed)...
> > Hi,
> >
> > how can I create an instance (object) of a class (form) if I only know
the
> > classname (VB.NET 1.0)?
> > I need to do this in a complex app where jobs consist of parts. Each
> > part's
> > data is saved in a separate database table. For the parts, the form's
> > class
> > name is saved in a data table, so that I know which form to use. As this
> > is
> > a string, I need to be able to create the form by it's name (like
> > CreateObject() does for COM objects).
> >
> > --
> > Any help gladly appreciated!
> >
> > Rene Mansveld
> > Spider IT - Germany
> > www.Spider-IT.de / www.Spider-IT.net
> >
> > Please reply to the newsgroup(s) )
> >
> >
>
>

It's solved now!

I got an answer from the german newsgroup from Jürgen Luhr which did it.
It is done through Reflexion:

'<deklaration code>
Imports System.Reflexion

'<routine code>
Dim t As Type = Type.GetType("<Namespace>.<Class>")
Dim c As ConstructorInfo = t.GetConstructor(Type.EmptyTypes)
Dim o As Object = c.Invoke(Nothing)
'Now o holds the instance of the class

--
Hope this helps ...

Rene Mansveld
Spider IT - Germany
www.Spider-IT.de / www.Spider-IT.net

Please reply to the newsgroup(s) )

"Rene Mansveld" <(E-Mail Removed)> schrieb im Newsbeitrag
news:(E-Mail Removed)...
> Thanks for the quick answer!
>
> Unfortunately I couldn't get this to work, and according to the help, this
> will create an instance of a Type.
> I tried the Activator.CreateInstance(Nothing, "Auftrag") call, but I got
> this exception:
> A non handled exception of type 'System.TypeLoadException' occured in
> mscorlib.dll.
> Extra info: The type Auftrag in the assembly ..., Version=0.3.1783.15723,
> Culture=neutral, PublicKeyToken=null could not be loaded.
> (translated from german)
>
> Any ideas anyone?
>
> --
> Rene Mansveld
> Spider IT - Germany
> www.Spider-IT.de / www.Spider-IT.net
>
> Please reply to the newsgroup(s) )
>
> "Imran Koradia" <(E-Mail Removed)> schrieb im Newsbeitrag
> news:(E-Mail Removed)...
> > take a look at the Activator.CreateInstance method in the
> System.Reflection
> > namespace.
> >
> > hope that helps..
> > Imran.
> >
> > "Rene Mansveld" <(E-Mail Removed)> wrote in message
> > news:%(E-Mail Removed)...
> > > Hi,
> > >
> > > how can I create an instance (object) of a class (form) if I only know
> the
> > > classname (VB.NET 1.0)?
> > > I need to do this in a complex app where jobs consist of parts. Each
> > > part's
> > > data is saved in a separate database table. For the parts, the form's
> > > class
> > > name is saved in a data table, so that I know which form to use. As
this
> > > is
> > > a string, I need to be able to create the form by it's name (like
> > > CreateObject() does for COM objects).
> > >
> > > --
> > > Any help gladly appreciated!
> > >
> > > Rene Mansveld
> > > Spider IT - Germany
> > > www.Spider-IT.de / www.Spider-IT.net
> > >
> > > Please reply to the newsgroup(s) )
> > >
> > >
> >
> >
>
>

Correction: Reflexion should be Reflection ;o)

--
Hope this helps ...

Rene Mansveld
Spider IT - Germany
www.Spider-IT.de / www.Spider-IT.net

Please reply to the newsgroup(s) )


"Rene Mansveld" <(E-Mail Removed)> schrieb im Newsbeitrag
news:(E-Mail Removed)...
> It's solved now!
>
> I got an answer from the german newsgroup from Jürgen Luhr which did it.
> It is done through Reflexion:
>
> '<deklaration code>
> Imports System.Reflexion
>
> '<routine code>
> Dim t As Type = Type.GetType("<Namespace>.<Class>")
> Dim c As ConstructorInfo = t.GetConstructor(Type.EmptyTypes)
> Dim o As Object = c.Invoke(Nothing)
> 'Now o holds the instance of the class
>
> --
> Hope this helps ...
>
> Rene Mansveld
> Spider IT - Germany
> www.Spider-IT.de / www.Spider-IT.net
>
> Please reply to the newsgroup(s) )
>
> "Rene Mansveld" <(E-Mail Removed)> schrieb im
Newsbeitrag
> news:(E-Mail Removed)...
> > Thanks for the quick answer!
> >
> > Unfortunately I couldn't get this to work, and according to the help,
this
> > will create an instance of a Type.
> > I tried the Activator.CreateInstance(Nothing, "Auftrag") call, but I got
> > this exception:
> > A non handled exception of type 'System.TypeLoadException' occured in
> > mscorlib.dll.
> > Extra info: The type Auftrag in the assembly ...,
Version=0.3.1783.15723,
> > Culture=neutral, PublicKeyToken=null could not be loaded.
> > (translated from german)
> >
> > Any ideas anyone?
> >
> > --
> > Rene Mansveld
> > Spider IT - Germany
> > www.Spider-IT.de / www.Spider-IT.net
> >
> > Please reply to the newsgroup(s) )
> >
> > "Imran Koradia" <(E-Mail Removed)> schrieb im Newsbeitrag
> > news:(E-Mail Removed)...
> > > take a look at the Activator.CreateInstance method in the
> > System.Reflection
> > > namespace.
> > >
> > > hope that helps..
> > > Imran.
> > >
> > > "Rene Mansveld" <(E-Mail Removed)> wrote in message
> > > news:%(E-Mail Removed)...
> > > > Hi,
> > > >
> > > > how can I create an instance (object) of a class (form) if I only
know
> > the
> > > > classname (VB.NET 1.0)?
> > > > I need to do this in a complex app where jobs consist of parts. Each
> > > > part's
> > > > data is saved in a separate database table. For the parts, the
form's
> > > > class
> > > > name is saved in a data table, so that I know which form to use. As
> this
> > > > is
> > > > a string, I need to be able to create the form by it's name (like
> > > > CreateObject() does for COM objects).
> > > >
> > > > --
> > > > Any help gladly appreciated!
> > > >
> > > > Rene Mansveld
> > > > Spider IT - Germany
> > > > www.Spider-IT.de / www.Spider-IT.net
> > > >
> > > > Please reply to the newsgroup(s) )
> > > >
> > > >
> > >
> > >
> >
> >
>
>

Well - its the same with Activator.CreateInstance. You get the type object
from the namespace and class name and pass in the type object to the method:

Dim t As Type = Type.GetType("<Namespace>.<Class>")
Dim frm As Object = Activator.CreateInstance(t)
DirectCast(frm, Form).Show()


Imran.


"Rene Mansveld" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> It's solved now!
>
> I got an answer from the german newsgroup from Jürgen Luhr which did it.
> It is done through Reflexion:
>
> '<deklaration code>
> Imports System.Reflexion
>
> '<routine code>
> Dim t As Type = Type.GetType("<Namespace>.<Class>")
> Dim c As ConstructorInfo = t.GetConstructor(Type.EmptyTypes)
> Dim o As Object = c.Invoke(Nothing)
> 'Now o holds the instance of the class
>
> --
> Hope this helps ...
>
> Rene Mansveld
> Spider IT - Germany
> www.Spider-IT.de / www.Spider-IT.net
>
> Please reply to the newsgroup(s) )
>
> "Rene Mansveld" <(E-Mail Removed)> schrieb im
Newsbeitrag
> news:(E-Mail Removed)...
> > Thanks for the quick answer!
> >
> > Unfortunately I couldn't get this to work, and according to the help,
this
> > will create an instance of a Type.
> > I tried the Activator.CreateInstance(Nothing, "Auftrag") call, but I got
> > this exception:
> > A non handled exception of type 'System.TypeLoadException' occured in
> > mscorlib.dll.
> > Extra info: The type Auftrag in the assembly ...,
Version=0.3.1783.15723,
> > Culture=neutral, PublicKeyToken=null could not be loaded.
> > (translated from german)
> >
> > Any ideas anyone?
> >
> > --
> > Rene Mansveld
> > Spider IT - Germany
> > www.Spider-IT.de / www.Spider-IT.net
> >
> > Please reply to the newsgroup(s) )
> >
> > "Imran Koradia" <(E-Mail Removed)> schrieb im Newsbeitrag
> > news:(E-Mail Removed)...
> > > take a look at the Activator.CreateInstance method in the
> > System.Reflection
> > > namespace.
> > >
> > > hope that helps..
> > > Imran.
> > >
> > > "Rene Mansveld" <(E-Mail Removed)> wrote in message
> > > news:%(E-Mail Removed)...
> > > > Hi,
> > > >
> > > > how can I create an instance (object) of a class (form) if I only
know
> > the
> > > > classname (VB.NET 1.0)?
> > > > I need to do this in a complex app where jobs consist of parts. Each
> > > > part's
> > > > data is saved in a separate database table. For the parts, the
form's
> > > > class
> > > > name is saved in a data table, so that I know which form to use. As
> this
> > > > is
> > > > a string, I need to be able to create the form by it's name (like
> > > > CreateObject() does for COM objects).
> > > >
> > > > --
> > > > Any help gladly appreciated!
> > > >
> > > > Rene Mansveld
> > > > Spider IT - Germany
> > > > www.Spider-IT.de / www.Spider-IT.net
> > > >
> > > > Please reply to the newsgroup(s) )
> > > >
> > > >
> > >
> > >
> >
> >
>
>

"Rene Mansveld" <(E-Mail Removed)> schrieb:
> how can I create an instance (object) of a class (form) if I only know the
> classname (VB.NET 1.0)?

\\\
Private Function CreateClassByName( _
ByVal PartialAssemblyName As String, _
ByVal QualifiedClassName As String _
) As Object
Return _
Activator.CreateInstance( _
[Assembly].LoadWithPartialName( _
PartialAssemblyName _
).GetType(QualifiedClassName) _
)
End Function
///

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