Make List Box Default Equal to Collection

[iwonder]

Thank you for taking the time to read my question.

I have a Multi-Select List Box in my app. I have a Collection of values that I create based on a LookUp on a SQL view.

I want to select all the rows in the List Box that are equal to the values in the Collection. I need this because I want to make my screen equal to an existing record in a SQL table. I don't want to use Forms as it's not flexible enough for my needs.

I'm not sure how to refer to the List Box values...

If I type in the List Box name and then do a dot after it, no options come up and IHNumbers has a red line under it.

List Box Default: 

If(IsBlank(recID),false, IHNumbers in collExistingHNum)

collExistingHNum is my collection

List Box name is: IHNumbers

recID is a global variable I set in the app elsewhere

Thanks!

[Drrickryp · Accepted solution]

Hi @iwonder 

It is not possible to set a default value for a multiselect listbox. ref: https://powerusers.microsoft.com/t5/Building-Power-Apps/Default-Selected-Values-Listbox/td-p/61338 
Here is an alternative before you make yourself nuts trying to do it.https://powerapps.microsoft.com/en-us/blog/supporting-multi-valued-listboxes-in-powerapps/ 

[iwonder]

Hi @Drrickryp 

Thank you very much for your reply.

I tried to use Forms but my need for a Gallery has forced me away from using it.

thank you for sharing that post. I have another gallery that I update using the Default function/feature. I'll change my List Boxes to Gallery's. 

Thanks!