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Regular Visitor

Duplicate Warning

Hey everyone,


I am currently facing a challenge. I am creating an event app in which users will attend sessions they favourite, this favourite list will appear and display the selected sessions. This is all fine, however, I only want a user to be able to select one session during the available time slot i.e. from 10am-11am there are two available session and you can only choose one of them, if you choose both a warning appears to indicate that you already have a session booked during that time slot. 


How am I able to create this duplication warning? Would I use conditional formatting i.e. If Repeated Twice, Colour 1 otherwise Colour 2. Or is there another way?


Thank you!!

Community Support
Community Support

Hi @Sierra_Alpha ,


What is the data source and what is the control that you use to select the sessions in this app? 




Community Support Team _ Mona Li
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

Hi Mona,


I am using CDS as my data source. So when I select the session, I have added a favourite button which adds that session to a new screen. The formula I am using is:


If(ThisItem.cr4f6_sessionid exactin (Filter([@'User Selected Sessions'],cr4f6_AttendeeIDV2.'Attendee Email'=User().Email)).cr4f6_SessionID.cr4f6_sessionid,
Remove([@'User Selected Sessions'],Filter([@'User Selected Sessions'],cr4f6_AttendeeIDV2.'Attendee Email'= User().Email,cr4f6_SessionID.cr4f6_sessionid=ThisItem.cr4f6_sessionid)),
Patch([@'User Selected Sessions'],
Defaults([@'User Selected Sessions']),{
cr4f6_SessionID:(LookUp('Session Workshops',cr4f6_sessionid=ThisItem.cr4f6_sessionid))}))


All I want it to do now is warn me that I aleady have a session booked and cannot book another session during the same time period.


Kind regards,


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