This simply depends on your database design.
You need to have table like this,
Item
+ ItemID | int | PK
+ ItemName | varchar
Vendor
+ VendorId | int | PK
+ VendorName | varchar
+ ItemId | int | FK
Now the query,
SELECT * FROM Item i, Vendor v WHERE i.VendorId = v.VendorId AND i.ItemId = @itemId
here
@itemId
is passed from your gridview.
And the code,
SqlCommand cmd = new SqlCommand(SELECT * FROM Item i, Vendor v WHERE i.VendorId = v.VendorId AND i.ItemId = @itemId, conObject);
cmd.Paramaters.AddWithValue("@itemId", itemId);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
foreach(DataRow dr in dt.Rows)
{
YourLabel.Text = dr["YourColumn"].ToString();
}
Hope you got the idea.. :)
-KR