Use this algorithm :
Create public variable on class name it as "Global_TaskID"
On selection of DGV on parent window update the Global_TaskID
on child form load event use this :
SELECT Task_ID, Project_ID, Description_, Priority_Level, Sub_Level, Requested_Date, Comments, Fixed_Date, Software_Version, Requested_By FROM dbo.tasks WHERE Task_ID = Global_TaskID
Then use this