This error comes up often for this control and workarounds have been discussed and posted.  See below

http://www.telerik.com/forums/radcombobox-error-selection-out-of-range-parameter-name-value 
http://www.telerik.com/forums/selection-out-of-range-excpetion 
http://www.telerik.com/forums/selection-out-of-range-parameter-name-error-need-to-be-able-to-set-values-that-don-t-exist-in-the-combobox 
http://www.telerik.com/forums/selection-out-of-range-parameter-name-value 
http://www.telerik.com/forums/selection-out-of-range-parameter-name-value-radcombobox-in-radgrid
http://www.telerik.com/forums/radcombobox-selection-out-of-range-error 
 

The feature request is the following:

1.  Add an Attribute to the RadComboBox, RadDropdownList (and any other controls that suffer from this issue).

2. Let's call the Attribute   --   AppendIfSelectedValueMissing.

3. This attribute would be a boolean (True / False).  Default is FALSE.

4. If AppendIfSelectedValueMissing=True  then when the value of record is being Databound to a RadComboBox, RadDropDownList, etc.  A check (or Try/Catch) would occur to ensure that the Value exists in the DataSourceList and if it does NOT exist in the list then the SelectedValue would be Appended to the List.  Thus, eliminating the "Selection out of range, Parameter, Value" error.

This occur often because some lists get changed over time; however, the historical data may have a value that is no longer on the list -- thus triggering the error.

For example, let's say we ask for a user's Favorite Color.  Our original list was:
Red, Green, Blue

but for some reason -- management, changing user requirements, etc. the new list is

Red, Orange, Blue

Now, if we DataBind a RadComboBox to a historical record with Green as value, we get the "Selection Out of Range" errror.

What I am proposing is -- if we set the AppendIfSelectedValueMissing = True then 
databinding to a historical record with Green would have the following occur.

List from DB ---   Red, Orange, Blue
SelectedValue --    Green
AppendIfSelectedValueMissing
New List for Ctrl --  Red, Orange, Blue, Green

Thus, the error goes away, the historical data can stay the way it is and the lists can adjust their choices over time.

All good for everyone!!!

Thanks for your consideration. 

Using the client-side requestItems method of a RadComboBox to fire the refresh of it's items(with a call to clearCache before to ensure that the refresh is performed), doesn't always perform the async callback request, sometimes resulting in the "Loading" text being added at the top of the combo's items drop-down and staying there (as the callback to the server is never fired, so it's result never received). 

After quite a bit of trials, I finally managed to figure out that the issue arise when there is an async postback in progress on the page (to refresh an update panel) when requestItems is called.

Stepping through the requestItems call with IE F12 tools, I found that this is due to the fact that the Sys.WebForms.PageRequestManager do not perform callbacks if there is an async postback in progress. I think that the RadComboBox should detect that situation and wait until the end of the async postback to fire it's requestItems callback, otherwise the combo get stuck in the "loading in progress" state, waiting for the end of the callback that will never happens as the PageRequestManager did not start it. Additionally, in F12 Network tab, I can see that there is no request performed for the callback to request the items of the combo-box.

I reproduce the issue with the following steps:
1- Have a page with a RadComboBox, a ScriptManager with partial rendering enabled and an UpdatePanel.
2- In the browser, trigger the async postback to refresh the UpdatePanel
3- From JavaScript, while the async postback is in progress, call the requestItems method of the RadComboBox
4- Open the drop-down of the combo, and you can see the "Loading" text at the top, with the initial list of items. And it stays like this until another call is made to requestItems when there is no async post-back in progress which will actually perform the callback.

MarkFirstMatch and Filter functionalities are not supported when checkboxes are enabled, as specified in the Checkbox Support help article. If you remove these two functionalities, the Check All checkbox works as expected.


I want to have on the MarkFirstMatch and the filter on and the "all" to be shown.

see ticket number 942452