Hello everyone :) I'm developing a web based form in which two or more Multiple-selection List Boxes ("MLB") are "in cascade". That means that different data would be loaded on the second MLB depending on which options are marked on the first MLB.
As filtering over these kind of controls causes innecesary postbacks to the Sharepoint Server, I decided to use OData REST web services (something extremely flexible for querying for data instead of common data connections, learnt thanks to this community).
The OData REST URL is dynamically updated, on any change on the first MLB. And here comes the problem:
- Changes on MLB seems to be handled only when selecting items, but not when deselecting.
- On the other hand, I'm using an extra field with the "eval" function to retrieve items selected on first MLB and dynamically update OData REST URL (as I said before). It updates perfectly on both marking and unmarking items on MLB. But I cannot assign the "Query for data" action to the "change" event of this control because this warning message is shown (it works though after closing the warning): "XML data that is required for this form to function correctly cannot be found." It is shown any time the form is renderized.
So, to summarize, querying for data works perfectly when assigned to MLB change event, -as well as if assigned to a button press or anythin "manually" changed- but unmarking items in MLB does not trigger the event.
Assigning "query for data" to a change event on a control that is "automatically" changed works, but the warning message is shown, so it is not a valid approach unless this warning could be ommited.
So, any help to this matter would be really appreciated.
(Obviously, I'm not allowed to use a button or anything that includes extra clicks to query for data. Second MLB must be updated on first MLB changes). A capture is attached just for clarifying ;) Thank you very much!!