How to correctly select a listbox item so a selection change occurs

2 posts, 0 answers
  1. Tim
    Tim avatar
    57 posts
    Member since:
    Apr 2011

    Posted 09 Dec 2011 Link to this post


    I have what I thought was a very simple requirement, and maybe it is.

    I have a ListBox that contains a few items, that I add programmatically in Server side code.

    As each item is selected I want to dynammically load a use control and present it to the right of the ListBox.

    Actually I have all of this working just fine.
    Again I am using a server side selection changed event to control the dynamic loading. 

    However I would like to set the intial selection to the first item in the listbox.
    I have tried to do this after the LB is loaded, and I have set the first item to selected just before adding it to the LB.

    In neither case do I get a selection change event so I can load the initial dynamic control.

    What am I missing?

    Do I just have to write extra code to load this control seperate from the SelectionChanged event I am relying on now?

  2. Bozhidar
    Bozhidar avatar
    1146 posts

    Posted 09 Dec 2011 Link to this post

    Hi Tim,

    If you want to load an initial user control, I would suggest that you do it in the Page_Load server event. If you use the selection changed mechanism for loading the initial user control, you make an unnecessary postback. Try the following:

    1. Extract all the code from the RadListBox1_SelectedIndexChanged event handler in a function, and in the handler just call the function. You can pass the index or value to the function, to determine which listbox item was selected

    2. In the Page_Load event handler, if the page isn't a postback, call the same method (with argument 0, if you are using index to determine the listbox item)

    Hope this is helpful.

    the Telerik team
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