ActiveX Component Expert

Posted on 1998-05-05
Last Modified: 2010-04-06
When I try to convert my component to an ActiveX control using the ActiveX expert (New ... ActiveX ... ActiveXControl), my component is not visible in the dropdownlist of VCL components. It is correctly installed and working as normal VCL component though, any ideas?
Question by:arnoldu
  • 3

Expert Comment

ID: 1341377
What does your component inherit from?


Author Comment

ID: 1341378
The component is inherited from TComponent - is there a problem with invisible components?

Accepted Solution

JimBob091197 earned 200 total points
ID: 1341379
Yip.  You can't have anything inherited directly from TComponent.  It must be a control (inherited from TCustomControl, or maybe TControl).

You could try changing it from "TMyWhatsIt = class(TComponent)" to TMyWhatsIt = class(TCustomControl)" and then in the constructor setting the Width & Height to 24, and keeping the Visible property False.  A bit of a work-around, but it should work.


Expert Comment

ID: 1341380
According to Delphi's help, a TActiveXControl must be derived from a TWinControl.

"TActiveXControl defines the core behavior and interfaces required of an ActiveX control and connects that behavior to any VCL control derived from TWinControl."


Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

The uses clause is one of those things that just tends to grow and grow. Most of the time this is in the main form, as it's from this form that all others are called. If you have a big application (including many forms), the uses clause in the in…
Creating an auto free TStringList The TStringList is a basic and frequently used object in Delphi. On many occasions, you may want to create a temporary list, process some items in the list and be done with the list. In such cases, you have to…
This video shows how to remove a single email address from the Outlook 2010 Auto Suggestion memory. NOTE: For Outlook 2016 and 2013 perform the exact same steps. Open a new email: Click the New email button in Outlook. Start typing the address: …
When you create an app prototype with Adobe XD, you can insert system screens -- sharing or Control Center, for example -- with just a few clicks. This video shows you how. You can take the full course on Experts Exchange at

943 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

16 Experts available now in Live!

Get 1:1 Help Now