sealed UI classes

[DotNetInterest]

Hi guys, I find (especially in .NET 1.1) that many UI type classes are kept "sealed". Any specific reason for that? Examples: Classes like Tooltip, Progressbar etc. Typcially, UI classes are supposed to be extensible. I can understand if 3rd party vendors keep their UI classes sealed (for more business oppurtunity ;-)) and therefore only provide developers to extended the functionality by providing properties or other extension mechanisms like interfaces on the controls/components (for custom rendering of the component) etc. But why would Framework providers like Microsoft, keep their (of course, not all!) UI classes sealed?

[Pete OHanlon]

One particular reason is so that you can't end up doing something that breaks the underlying object. Bear in mind that some of the controls are effectively wrappers for API calls you can appreciate that it would be very easy for you to do something that just broke them.

Deja View - the feeling that you've seen this post before.

[Jaiprakash M Bankolli]

My understanding is that classes like Tooltip etc are final form of any feature/ UI type. If you try to customse it you will not achieve much ... so they are SEALED. This make the developer use it as it is in either custome or user control

Regards, Jaiprakash M Bankolli jaiprakash.bankolli@gmail.com Blog: http://jaiprakash.blog.com/ Suggestions: http://jaitoimprove.blog.com/