System.NullreferenceException: Object reference not set.... - Wizard for Windows Forms Forum

Posted 18 years ago by SR

Hiya

Aaaagh! Am getting a "System.NullreferenceException: Object reference not set to an instance of an object" error in design mode with Wizard when switching to the first interior page: Wizard is using a single ControlLibrary control on this page (which BTW is in turn inherited from another control in the lib) in the Windows control library. This is in a VS.Net 2003 / XP SP2 environment.

Have basic screenshot but no way of attaching here, so please can you advise how best we should proceed with looking at this problem?

Please could you reply via email on this one? You will no doubt want background info and code and I don't wish to post any of that here at this time.

Many Thanx

Scott

Comments (2)

Posted 18 years ago by SR

(ps Have sent screen shot via email to Actipro Support em a/c)

Posted 18 years ago by SR

Hi

Just to say that it turns out that this occurred because I had unintentionally changed a Control Library User control to become effectively an abstract class using MustInherit and MustOverride.

The previous version of the inherited control(s) that were placed on the Wizard's pages suddenly contained an invalid design-mode control version and hence the reason why your component threw this unexpected error.

So. My fault, not yours.

- thanks for all the swift responses to my questions.

SR

The latest build of this product (v24.1.0) was released 3 months ago, which was after the last post in this thread.

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