Insert Sequence Number Function into an Item Gallery

[vsslasd]

In an Gallery for the Item Property, I have the following definition:
ForAll(Filter(MR_POH,JobNo=Job_Gallery.Selected.JobNo &&
(Dropdown1.Selected.Value=Status || Dropdown1.Selected.Value="ALL")) As _item,
With(LookUp(
DropColumns(
AddColumns(
GroupBy('[dbo].[MR_POL]',"PackageNo","GroupedItems"),
"QTYSUM",Sum(GroupedItems,QTY)
),
"GroupedItems"),
PackageNo = _item.PackageNo),
Patch(_item,
{
QtySum: QTYSUM
})))

I'd like to include a sequential row number for each row using the Sequence function returned in above result set. 

Sequence function in Power Apps - Power Apps | Microsoft Docs

Thank you

[CarlosFigueira · Accepted solution]

It's not pretty, but if you have an items property set to the expression X, you can add an index to it using an expression similar to the one below:

With(
  { coll:X },
  ForAll(
    RenameColumns(Sequence(CountRows(coll)),"Value","Index") As Idx,
    Patch(Idx, Last(FirstN(coll, Idx.Index)))))

For your scenario, if you replace 'X' in the expression above with your original expression, you should get a new column called 'Index' in your gallery, something like the expression below:

With(
    { coll: ForAll(
        Filter(
            MR_POH,
            JobNo = Job_Gallery.Selected.JobNo && (Dropdown1.Selected.Value = Status || Dropdown1.Selected.Value = "ALL")) As _item,
        With(
            LookUp(
                DropColumns(
                    AddColumns(
                        GroupBy('[dbo].[MR_POL]', "PackageNo", "GroupedItems"),
                        "QTYSUM", Sum(GroupedItems, QTY)),
                    "GroupedItems"),
                PackageNo = _item.PackageNo),
            Patch(_item, { QtySum: QTYSUM })))
    },
    ForAll(
        RenameColumns(Sequence(CountRows(coll)),"Value","Index") As Idx,
        Patch(Idx, Last(FirstN(coll, Idx.Index)))))

Hope this helps!