TabControl and Visual Inheritance

[Andrew]

Hello,

I'm experiencing some strange behavior when trying to derive a form from a base from that contains a TabControlExt.

I cannot select/edit the individual tabs (using the designer) that belong to the TabConrtolExt on the derived form. I have made sure that I the TabControlExt on the base form is declared as Protected.

Also, I often get a error stating that the "Object reference is not set to an instance of an object." within the VS.NET environment for the derived form. When this error occurs you cannot view the form in the windows designer.

Is there something that I need to do when using visual inheritance and the tab control. I recall reading on the forums that the Essential Grid does not support visual inheritance, is this the case for the TabControlExt as well?

[Arun Srinivasan]

Hi Andrew,

We were unable to reproduce the problem here. I followed the steps you describe above to create a sample which I have uploaded for reference.

Can you tell us which version of Essential Suite you are currently using? I tried this on Windows XP/ VS .NET 2003 using Essential Suite 1.6.1.0.

Thanks
Arun

[Andrew]

That's the exact same configuration that I am using. I'll try it again and let you know what happens.

Thanks,

Andrew

> Hi Andrew,
>
> We were unable to reproduce the problem here. I followed the steps you describe above to create a sample which I have uploaded for reference.
>
> Can you tell us which version of Essential Suite you are currently using? I tried this on Windows XP/ VS .NET 2003 using Essential Suite 1.6.1.0.
>
> Thanks
> Arun
>

[Andrew]

Team,

I got rid of all the errors (Object reference is not set to an instance of an object, and the strange tab control behavior) by doing the following:

- I created a new solution and new projects under that solution. I imported the code files under their appropriate projects (the structure is the same as the old solution). This immediately fixed the tab control problem. It is now working fine. However, I was still getting the "Object reference is not set to an instance of an object" error from within the Visual Studio .NET 2003 environment.

- I was using XP Home Edition when I was getting the errors mentioned above. After I created the new project I ran out and purchased a copy of Windows XP Professional.

After installing Windows XP Professional I loaded up the solution and that was the end of the errors. It hasn't given me a single error since.

Any ideas??

Andrew

> Hi Andrew,
>
> We were unable to reproduce the problem here. I followed the steps you describe above to create a sample which I have uploaded for reference.
>
> Can you tell us which version of Essential Suite you are currently using? I tried this on Windows XP/ VS .NET 2003 using Essential Suite 1.6.1.0.
>
> Thanks
> Arun
>