How to prevent duplicate values with autocomplete?

[Paul]

I have been looking at the demo with the auto complete ​functionality of the emails with the separator. It seems that if you select an email and separate it and add another email, you can select the exact same email again. For example this could be possible selection: [e-mail], [e-mail], [e-mail], [e-mail]. Is there a way to prevent the entry from being selected again?

[Nencho]

Hello Paul,

I am afraid that in such scenario you cannot prevent the end-user from duplicating the added item, This is why, I would suggest you a slightly different scenario - you can implement the CheckBoxes functionality of the RadComboBox, along with filter field, on order to facilitate the user selection.

In the attachment you can find a simple example on how the above suggest approach could be implemented.

Regards,
Nencho
Telerik