Using MustInerit with Forms

[nate axtell]

Using VB.NET 2003 in Visual Studio...
I have created a base Form class ProjectA.FormA, that I inherit in another
class called ProjectB.FormB. FormA is declared as MustInherit. When I try
to view the inheriting class FormB in the Visual Studio Designer I see the
error:
"The designer must create and instance of 'ProjectA.FormA ' but it cannot
because the type is declared as abstract."
If I remove the MustInherit and rebuild ProjectA then FormB is displayed
without the error. Has anyone found a way to use MustInherit in a base
class definition and then view the inheriting forms in the designer?
thanks,
nate

[Herfried K. Wagner [MVP]]

Re: Using MustInerit with Forms

"nate axtell" <naxtell at progeny dot net> schrieb:[color=blue]
> I have created a base Form class ProjectA.FormA, that I inherit in another
> class called ProjectB.FormB. FormA is declared as MustInherit. When I
> try to view the inheriting class FormB in the Visual Studio Designer I see
> the error:
> "The designer must create and instance of 'ProjectA.FormA ' but it cannot
> because the type is declared as abstract."
> If I remove the MustInherit and rebuild ProjectA then FormB is displayed
> without the error. Has anyone found a way to use MustInherit in a base
> class definition and then view the inheriting forms in the designer?[/color]

That's a known limitation of the designer. You can partially work around it
by using this code:

\\\

' In the project properties the checkbox that defines the
' 'DEBUG' constant must be checked.
#If DEBUG Then
Public Class Foo
#Else
Public MustInherit Class Foo
#End If
...
End Class
///

In release mode the class will be 'MustInherit'.

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

[nate axtell]

Re: Using MustInerit with Forms

Thanks. I'll try it out.
[color=blue]
> That's a known limitation of the designer. You can partially work around
> it by using this code:
>
> \\\
>
> ' In the project properties the checkbox that defines the
> ' 'DEBUG' constant must be checked.
> #If DEBUG Then
> Public Class Foo
> #Else
> Public MustInherit Class Foo
> #End If
> ...
> End Class
> ///
>
> In release mode the class will be 'MustInherit'.
>
> --
> M S Herfried K. Wagner
> M V P <URL:http://dotnet.mvps.org/>
> V B <URL:http://dotnet.mvps.org/dotnet/faqs/>[/color]