I have two controls the first one is a Drop Down List and the second is a List Box.
When the Dropdwon List Selected Index Change trigers, the callback method updates the Lis Box.
NET AJAX is doing and how our Update Panel cross-panel triggers work. Both of these tools are freely available online, and can be found with an internet search.
To do so, we will work with the generated page source HTML, as well as the Mozilla Firefox extension called Fire Bug - with it, we can easily examine the AJAX postbacks. An examination of the page source code shows almost nothing out of the ordinary; the Update Panel controls are rendered as containers.
So I compared the web.config files and I noticed that the generated web.config file had additional configuration lines than that of the ones from the installation instructions. Atlas is still in pre-release, so it's officially not supported by Microsoft.
I put those two controls inside an Update Panel, but the Update Panel is not UPDATING. Update(); directly, but that does not update the neither.However, if the parent Update Panel is refreshed, then the child Update Panel will also be refreshed.When working in the markup editor in Visual Studio, you may notice (from Intelli Sense) that there are two child elements of an , and can specify any Control within the current unit of encapsulation (for instance, if your Update Panel control resides within a Web User Control, you should not attempt to reference a Control on the Page on which the User Control will reside).I have a Image Button that does a postback to get the user control to display itself with a grid containing data in it. The user control which has the grid is enclosed within an upatepanel with the trigger set to the "Control Event Trigger Event" with the Image Button control.When I run the page annd click on the Image Button it throws an "Unknown Error" message box and the usercontrol doesn't refresh.
So, I wrapped it in the atlas:update panel with the scriptmanager and updatepanel set the same as nnassar's.