SQL to DAX conversion

Happy New Year, pal! Thanks for tagging me for some tricky game of DAX.

I'm afraid you were mislead by PO's sql; first of all, I simplied it this way,

declare @Transdate datetime
declare @warehouse nvarchar(225)
declare @province nvarchar(225)

set @Transdate = '2016-07-11 00:00:00.000'
set @province = 'BC'
set @warehouse = 'BC-52'
;

with main1 as (
SELECT 
	*
	, ROW_NUMBER() OVER(Partition by itemid   ORDER BY transdate DESC) AS [rn]
	, SUM([Amount]) OVER (PARTITION BY ItemID) AS [Total]
FROM [dbo].[MATDW SAMPLE DATA] dt
WHERE  transdate <=  @Transdate
and province = @province
and warehouseid = @warehouse)

select * from main1 where [rn]=1

DAX

Total = 
VAR __cat = MAX( 'MATDW SAMPLE DATA'[Category] )
VAR __summary =
    CALCULATETABLE(
        ADDCOLUMNS(
            ADDCOLUMNS(
                SUMMARIZE(
                    'MATDW SAMPLE DATA',
                    'MATDW SAMPLE DATA'[ITEMID],
                    'MATDW SAMPLE DATA'[WarehouseID]
                ),
                "@amt", CALCULATE( SUM( 'MATDW SAMPLE DATA'[Amount] ) ),
                "@maxdate", CALCULATE( MAX( 'MATDW SAMPLE DATA'[TRANSDATE] ) )
            ),
            "@Cat",
                VAR __dt = [@maxdate]
                RETURN
                    CALCULATE(
                        MAX( 'MATDW SAMPLE DATA'[Category] ),
                        'MATDW SAMPLE DATA'[TRANSDATE] = __dt
                    )
        ),
        ALLSELECTED( 'MATDW SAMPLE DATA'[Category] )
    )
RETURN
    IF(
        __cat IN SELECTCOLUMNS( __summary, "_cat", [@Cat] ),
        SUMX( FILTER( __summary, [@Cat] = __cat ), [@amt] )
    )