The only control that cannot be used in the update panel is File Upload Control. By Default property of update panel’s update mode is always, which means on the update of one update panel the rest of update panels get automatically updated. We can set the update mode property to conditional, which will update the update panel on some condition like on the update of update panel 2 the update panel 3 will gets automatically and the rest of update panels will remain unchanged. We can use triggers in ajax only when it is set to conditional mode. Triggers are helpful when we want to associate the change in the event of any control with the update panel’s ID. For example on the event of selected index changed of dropdown the update’s panel content should be updated.
Ajax extensions in asp.net
With the installation of ajax extension dll file to the visual studio. We can extend the functionality of the controls. Asp.net offer wide range of functionalities with ajax extension toolkit such as Modal Popup, Collapsible Panel , Accordion, Filtered TextBox for validations, TextBox Watermark, Toggle Button to use the custom images to show the state of the CheckBox , Review Rating etc.
Ajax with master page
Place script managerin the master page and the update panel in the content pages. We need to write the following code in the page load event of master page.
The most commonly seen ajax examples are chat functionalities, Auto Complete Extender of google search engine, facebook search bar, google maps, progress bar and calendar controls and file upload control with the functionality of type check with progress bar, drag drop and ability to multiple upload of files. Ajax enhances in user interactivity on the web and better user web experience by saving lots of time and effort.