I have the following requirements and I am trying to get some telerik control to work but it seems I cannot achieve all the requirements.
I need a multi-select control. I do not want to load the data on page load for performance reasons. When the user clicks on the dropdown that is when I want to load all items and show it to the user. It does not require client filtering but if it works then its a bonus.
The user then selects the multiple options and a button is pressed. In the postback I need to pick up the options that were selected.
I have tried the RadCombobox but if you use LOD then checkboxes are not supported. I tried using itemtemplate with a checkbox in it but I was not able to pick up the selected checkboxes after postback and the selections are not perserved after postback either. I have seen an example of this but the js function it uses needs the clientid of the radcombobox. I do not have this available at the right time in the page lifecycle. It is too complicated to get this because I am rendering these controls programmatically and dynamically.
I have tried to make this to work with radautocompletebox however I have a box where I have to type before I see the options. This is not acceptable for my requirements. When the user clicks on the autocomplete control I need to show them all options available. Then once they select and press the button I need them persisted and need to be able to pick them up in the post back.
Please advise if these controls can be made to meet my requirments or if you have another control that can achieve this? To summarise:
It must Load on Demand when the control is clicked
It must allow multi select
I must be able to pick up the selections in server side postback.