cannot otain value-C# WebForm

We have a complex Webform with lots of Controls. If I Enter Data and hit the Submit Button everything is fine. If I load Data into the Controls (maybe 45 Labels and 20 Textboxes), change a few of them and want to update, nothing works. While Debugging the Debugger says for every Control: cannot obtain value. I found a Website where they said that I hafe to call "invoke". But I have no Idea how to handle it. Does anyone have experience with this kind of Problem? Additional: Every Action on this Form is Postback. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform C#, ASP.NET, .Net-Framework 1.1