You need to create the Stored Procedure and write this Select Query in it.
SELECT * FROM tbltask
WHERE Taskdate BETWEEN DATEADD(WK, DATEDIFF(WK, 0, Taskdate), 0) AND DATEADD(WK, DATEDIFF(WK, 0, Taskdate) + 1, 0)
It will take the records between todays date and 6 days. If any record is available between these two dates then it will be shown in the GridView.