Protect multiple selection by CTRL key from list box

[#1]

How can I protect multiple selection from a listbox where user can't select more than 1 record by pressing CTRL key

User can select only 1 country at a time. Anyone can answer.

My question is very simple -

     1. No country will be select after reload data

     2. After reload when I select "Afghanistan", I can see only the expression against "Afghanistan"

     3. If I select "Albania" then "Afghanistan" will be deselect and can see only the expression against "Albania"

     4. If I press CTRL key and try to select both country "Afghanistan" and "Albania" then it will not work.

Anyone can give this answer by written not any qvw file? 

[#2]

Hi Santosh,

Enable  One Selected Value is partially correct but I need no country will be selected after loading. Here if I enable One Selected Value then always 1 country will be selected default after loading.

[santhoo_san]

Hi, Please see attached example. Subodh has already addressed this.

roche.subodh

[#4 · Accepted solution]

Set up a trigger for a field on an OnSelect event (Settings -> Document Properties -> Triggers). For field FIELD set up Selection -> Select in Field -> use =Only(FIELD) as Search String.