Hello,

I am trying to design a list view which has a drop down list as a source. I want to prevent the user from selecting the duplicate values from the drop down. I want to do it in one of the following ways

1. If the value is selected and added to the row, and the user goes to the next row the same value should not appear

2. If the value is selected and added to the row, and if the user selects the same value then they should get an error message saying that "Duplicate values cannot be selected"

Have been trying to do it through the rules implementation on List view, Form etc, but I have not been able to find a way yet.

Any help will be much appreciated.