Lookup items from one list based on column values in another list

[Sgriffin]

My PowerApps form contains a field that is a lookup column in a SP list (Eq. Master), the SP column is named ID (this column contains a static list of bar-code values).  

Without getting into the details of my PowerApps form and associated SP lists, I need to get suggestions on how to go about solving an issue (it's really a feature, that I'd like to have).  My app's Form collects details about specific equipment ID's and inserts the form content into a "target" SP list.  The user selects the specific Eq ID using a drop-down box (this is from a different SP list, I'll call it the "source" list).  Depending on the situation, the user can use two dropdowns, each pulling items from the same SP list/column (both dropdowns pull from the "source" list, Eq ID field).

Here's what I'd like to do: as items are "inserted" into the "target" list , I'd like to "remove" these IDs from the dropdown items the user selects from (both dropdowns).  So, the net effect is that once an ID has been added to the target list (in either ID field), then it does not appear as available to the user to select a second-time.  See attached image, I don't want the target list to have duplicate items between the two ID fields.  As you can see in the image, both ID One and ID two columns have a value of C1002, this is what I want to avoid.

I'm pretty much a novice at PowerApps, so please consider that when making suggestions.  Your assistance is appreciated.

SteveG

[v-monli-msft]

Hi @Sgriffin ,

I think this cannot be achieved using PowerApps, but you can make it work by setting from the SharePoint list side.

When creating the Lookup column "ID", please check the Enforce unique values to Yes. After this, this field would appear as a dropdown control inside the edit form and you will see the options from the source list. If user selects a value that has already in use, then he won't be able to save this item with the edit form.

Regards,

Mona

[Sgriffin]

Thanks for your reply, but I don't that will work because the SP list has two ID columns (you'll see an example of this in the image I uploaded).  Is there a way to enforce uniqueness between these two columns?

Thanks again.

[v-monli-msft]

Hi @Sgriffin ,

I'm afraid that this cannot be achieved. You cannot force unique between 2 columns.

Regards,

Mona