Why does PATCH keep adding rows instead of updating the collection?

Question

I've got a gallery on the screen with a text input field. When the value of the input field changes, I want to update the selected item with the new value but PATCH just keeps adding rows to the collection. I've got similar code on other screens that's working properly.

Patch(colAvailableItems, galNewOrder.Selected, {Qty: Value(txtNewOrderQty.Text)} );

The code to create the collection is on a button on a previous screen-

ClearCollect(datAvailableItems,'05bGetSkusForNewOrder'.Run(radProductType.Selected.Value, ddStore.Selected.LocationID, ddWeekNum.Selected.DeliveryDate, ddWeekNum.Selected.FiscalWeek, ddWeekNum.Selected.DistPOLocationID, ddWeekNum.Selected.OrderOnDate));

ClearCollect(colAvailableItems, RenameColumns(AddColumns(datAvailableItems, "Qty", 0, "Pieces", ThisRecord.BUM * "Qty"),"BUM", "CsPk"));

Navigate(storeNewOrder);

Any ideas?

Answer 1

Try this formula:

Select(Parent);
Patch(colAvailableItems, galNewOrder.Selected, {Qty: Value(txtNewOrderQty.Text)} );

Documentation: Select function in Power Apps

Answer 2

Not sure if it's the best way but it appears to be working. I'm using UpdateIf in lieu of PATCH, like so...

UpdateIf( colAvailableItems, (Qty = 0 && ExternalProductID = ThisItem.ExternalProductID), { Qty: Value(galNewOrderItems.Selected.txtNewOrderQty.Text) } )

No new rows getting added to the collection and the data is being written to the db properly.

Answer 3

Another way is to use LOOKUP in the Patch command to a unique identifier on the item.

Patch('DatasourceName', LookUp('DataSourceName', id = something.Selected.id), {NORMAL PATCH PARAMETERS })