Get Column name for an Insert Query from The Selected GridView Row

Hi Guys, I am trying to insert data in an SQL table by executing an Insert Query. 

The problem is that I need to get the column name from a cell in the selected gridview Row.

Here's the snippet:

SqlCommand cmd30 = new SqlCommand("insert into mytable ( '"+GridView7.SelectedRow.Cells[0].Text+"' , r_id) values ('"+ GridView7.SelectedRow.Cells[1].Text +"', '"+TextBox1.Text+"')",con30);
        cmd30.ExecuteNonQuery();

**r_id is not a Primary Key.

The Error is get is:

Incorrect syntax near 'r_id'.

Also is it possible to get the column name of the table from a specific cell of the selected Gridview row?

That seems to be the problem.

Any Help will be appreciated.

Thanks,

Shaleen