Enviando por email Delegation - Distinct values for a large list field in Combo Box Items

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D A T A , D E L E G A T I O N 
Delegation - Distinct values 
for a large list field in Combo 
Box Items 
07/08/2022 / 0 Comments 
This idea is an extension of a workaround in Combo Boxes dealing with large 
lists and the Delegation issues surrounding these and the Distinct function. I 
have tested this on a large list (30k items) and it works perfectly. 
Two caveats here – the number of items displayed in your combo box and the 
number of filtered items subject to the Distinct function (after the leading letters 
are entered) will both be subject to your Delegation Limit, but these should not 
generally be an issue. 
This example is using a big list Aircraft with a field Airline. The idea is to start 
typing the Airline name and all Distinct values starting with the input will then be 
avalable for selection in the Combo Box. There are two “tricks” here – one is to 
use the Combo Box SearchText to limit the fields available and then avoid the 
Delegation issue using a With() statement to “pre-filter” the output subject 
to Distinct. 
After that, the code is quite straight-forward. 
With( 
 { 
 wStart: 
 Filter( 
 Aircraft, 
 StartsWith( 
 Airline, 
 Self.SearchText 
 ) 
 ) 
 }, 
 Sort( 
 Distinct( 
 wStart, 
 Airline 
 ), 
 Result 
 ) 
) 
https://www.practicalpowerapps.com/category/data/
https://www.practicalpowerapps.com/category/delegation/
https://www.practicalpowerapps.com/delegation/distinctcomboboxitems/#respond
So at the top, it is grabbing all the field names starting with the Combo Box 
Search input – StartsWith() is Delegable, so this will work on any sized list, then 
providing the output of this (the user may have to type in a few more letters at 
times) is under your Delegation Limit, the Distinct function then operates (locally) 
and is not subject to Delegation. 
NOTE: You need to turn Allow Searching back on (it will automatically disable) in 
your Combo Box. You may also get a Delegation warning here, but you can 
ignore it. 
DelegationDistinct 
By Warren Belz 
https://www.practicalpowerapps.com/tag/delegation/
https://www.practicalpowerapps.com/tag/distinct/
https://www.practicalpowerapps.com/author/admin/