Get all the items inside SharePoint list which have their Ids inside a collection without raising any delegation errors

Question

I have 2 SharePoint lists:-

1. Parent_1.
2. Child2 . has a ParentId field which store the Parent_1 id in a single line of text.

Now i want to do these 2 operations:-

1. Build a collection which contain all the Parentid from the Child2 list.
2. set the Items property of a ComboBox to only contain the Parent_1 records which have an Id inside the collection. In other words the ComboBox should only contain Parent_1 records which are assigned to at-least one Child2 record.

Now i tried this Appraoch-1

Inside the Screen Onvisible, i built the following collection:-

ClearCollect(childcol,ShowColumns(Child2,"ParentId")); 

and inside the Item property i tired the following, but i got a delegation warning on the "in" operator:-

Filter(Parent_1, ID in childcol.ParentId).Title 

Then i tried Appraoch-2, where inside the screen OnVisible, i build the following 2 collections:-

ClearCollect(childcol,Child2, ["ParentId"]);
ForAll(childcol,Collect(parentcol,Filter(Parent_1,ID=childcol[@ID]))); 

then inside the Items property of the Combobox, i define the following:-

parentcol.Title 

I did not get any delegation warning but the ComboBox will be empty.

any advice how i can Get all the items inside SharePoint list which have their Ids inside a collection without raising any delegation errors

Answer 1

Try to use this -

ClearCollect(
    colChildDropDown,
    ForAll(
        Parent_1 As _items,
        If(
            !IsBlank(
                LookUp(
                    Child2,
                    ParentId = _items.ID
                ).ParentId
            ),
            {
                ID: _items.ID,
                Value: _items.Title
            }
        )
    )
)