Checking for selected values for AutoCompleteBox

[Benjamin]

Would like check if it is possible to not allow user from selecting items from the list when it has already being selected?

[Peter Milchev]

Hello Benjamin,

If you need an item to be selected only once, I recommend checking the MultiSelect control:

• https://demos.telerik.com/aspnet-ajax/multiselect/overview/defaultcs.aspx 

Otherwise, you can cancel the OnClientEntryAdding event if there is already a token with the same value:

• https://docs.telerik.com/devtools/aspnet-ajax/controls/autocompletebox/client-side-programming/events/oncliententryadding 

• function OnClientEntryAdding(sender, args) {
      var duplicates = sender.get_entries().toArray().filter(function (item) {
          return (item.get_text() == args.get_entry().get_text() &&
              item.get_value() == args.get_entry().get_value())
      });
      if (duplicates.length > 0) {
          // there is already a token with the same text and value
          args.set_cancel(true)
      }
  }

Regards,
Peter Milchev
Progress Telerik