Apparently the code is without errors, but running the page in debug mode, you receive an error like this:
By clicking on the button “Stop”, I’m going to try to understand what might have happened, and I realize that the object “_form” of the page does not exist, or is “null”
this._form is NULL
Needless to tell you how long I spent trying to figure out what could have happened, and where could be a possible error, of course without success.
After a meticulous search on the internet, I finally found an article that enlightened and saved me .
It seems to be a small bug of ScriptManager object, which misinterprets the tag <script /> without explicit locking.
It was sufficient change the tag and use the canonical syntax to solve it all:
To fully understand how to use ASP.NET is necessary to know the basic operation of the web (for example as occurs a request from browser to server, what are the technologies used, how a web server processes the request, etc. …).
Understanding why a web page is not interpreted correctly in a browser, because a request is not performed as expected, or generate the appropriate HTML code from a custom control, are questions that do not depend only on knowledge of ASP.NET (or any other technology), but also from the knowledge of how a web application works.