You need to use single query by using join on common column from both table and just need to modify your select query in stored procedure as per your GridView column design , also then you don’t need to add it into different DataTable you can bind dataset to GridView.
Check below test query how to make join two tables and make simple select output.
SQL
DECLARE @UserInfo AS TABLE(userid INT, userName VARCHAR(50))
DECLARE @UserAddress AS TABLE(userid int, Address1 VARCHAR(100),Address2 VARCHAR(100))
INSERT INTO @UserInfo VALUES(1,'Vikas')
,(2,'Vinayak')
INSERT INTO @UserAddress VALUES(1,'Mumbai','Goregaon')
,(2,'Mumbai','Dadar')
SELECT UA.userid,userName,Address1,Address2
FROM @UserInfo UI INNER JOIN @UserAddress UA ON UI.userid = UA.userid
OUTPUT
userid |
userName |
Address1 |
Address2 |
1 |
Vikas |
Mumbai |
Goregaon |
2 |
Vinayak |
Mumbai |
Dadar |