Could you explain your issue in greater detail? What do you have in mind with clearing the value in the server if you are using a webservice, which is stateless? Also, what does flashing when page is loading mean? If you have set the control to update on PageLoad or you have set its VIsibleOnPageLoad property to true it would show when the page is loaded.
For clearing the values upon closing from the [x] button - you can use the OnClientHiding event which exposes information whether the user clicked the close button: http://www.telerik.com/help/aspnet-ajax/notification-on-client-hiding.html
- the get_manualClose() method of the event arguments object. If this flag is true you can use the control's client-side API
to clear its text, e.g. set_text("").
I believe the following demos can illustrate the logic nicely:
- on using a webservice in general
- on updaring on a time interval and only showing if there is new content to show
If after that you still need to clear a certain value I would need more information on the problem and scenario in order to suggest a suitable idea. Generally, with webservices there isn't a state left on the server and if the notification is shown only if and when new content arrives you shouldn't need to clear anything else on the client, too.
Note that in the second demo the LoadContentOn is set to TimeInterval. The following article shows several common scenarios and explanations on how to combine the main properties of the control: http://www.telerik.com/help/aspnet-ajax/notification-server-side-overview.html
the Telerik team
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