DAX : How to SummarizeColumn with certain condition

Dear friends,

I have data that need to summarize, but at one of its column, I needed to show the last date (maximum date) on the related key row.

The data is something like this :

and the expection is to summarize this ItemId, Quantity, CostAmount, which is the 2 last column is easy (just use SUM), but the TransDate I want to retrieve only the last date when quantity is positive, like this :

I tried like this ->

Invetory = ADDCOLUMNS(
                        SUMMARIZECOLUMNS('inventory data'[ItemId], "Qty", SUM('inventory data'[Quantity]), "Amount", SUM('inventory data'[Cost amount]) ),
                        "InflowDate", MAX('inventory data'[TramsDate])
                        )

But the date is not the date of related ItemId, but the Max date overall, not to mentioned I don't know where to put the condition of the Quantity should be > 0.

Thanks