Custom component problem

[Raconteur]

Hi gang,

Not sure if this is the correct forum for this questions but here goes.

I have developed several custom web data components and built them into a
DLL. I reference the DLL in my VB.NET project, add a tab to the toolbar and
add the controls beneath the tab. This all works fine, and I can drag and
drop my controls on to the designer and all is good... until...

If I close the designer and try to reopen it, I get an error saying

"The file could not be loaded into the Web Forms designer. Please correct
the following error and then try loading it again:

Type Abstract

Make sure all of the classes used in the page are build or referenced in the
project."

If I click OK then the web form loads, but I can only look at the HTML, and
am unable to view the designer.

Can anyone shed any light on this problem??? I am stumped.

Cheers,

Chris

[Dincer Ozturan]

The components you have added into the new ToolBox tab loose the
reference to the new Component DLL; their relations are not refreshed
when you rebuild the project which contains components. I had the same
problems. I gave up dragging dropping from the toolbar; now adding the
html code and references manually directly in the HTML view of the
pages. Don't forget to remove the tab that contains the custom
component items.

Good Luck..

[Raconteur]

Hi Dincer,

Thanks for the reponse... but what do I do to get this to work? Why am I
getting the error, and what do I need to change in the HTML to rectify it?

Is this a known bug that is being worked on? I cannot believe that you just
cannot create custom controls that cannot be toolboxed...

Appreciate the help, but I need to find a solution, at least to being able
to open the deisgner.

[Raconteur]

Ok, I have figured out the problem, but am no closer to understanding it...

In my project that has my custom controls, I have subclassed
System.Web.UI.Page and System.Web.UI.UserControl. I have made my two
subclasses MustInherit because I have a property that must be implemented in
any of their subclasses (MustOverride).

The MustInherit seems to be the culprit. If I remove that, and make the
property Overridable, then everything is fine.

Is there some sort of problem with setting something in this heirarchy to
MustInherit? Or is this a bug?

Cheers,

Chris