How to another form text box values binding on second form data grid view empty cell.

Hello sir,
I am creating windows application using C# 2010 - Here i am using 3 forms
in my first form place a one data grid view and enter 6 rows but i am enter below format (it's stored at 2 empty rows)
EX :
Sl.No Name Age
1 A 10
2 B 11
3
4
5 C 12
6 D 13

Like this format - it's successfully stored at sql db.
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IN my second form i am using approximately 10text boxes and enter 10 text boxes vales stored at sql db.
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IN MY 3rd FORM
placed 2 drop down list and below one data grid view, here i am select 1st drop down(it's binding a first form db) records are display my 3rd form data grid view same as to form1 like below example,
but here i want
I am select a 2nd drop down binding a records 2nd form db. in my empty space cells how to display seconds form text box values as an row 3rd,& 4th rows.
Sl.No Name Age
1 A 10
2 B 11
3
4
5 C 12
6 D 13

any one give me suggestions.