Add values in gridview at runtime and save it to database?

public void Fill_grid()
     {
         SqlCommand cmd = con.CreateCommand();
         cmd.CommandType = CommandType.Text;
        cmd.CommandText = "select * from DBTable";
         cmd.ExecuteNonQuery();
         DataTable dt = new DataTable();
         SqlDataAdapter da = new SqlDataAdapter(cmd);
         da.Fill(dt);
         dataGridView1.DataSource = dt;

     }

     private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e)
     {
         id = dataGridView1.Rows[e.RowIndex].Cells["id"].Value.ToString();
         if (id == "")
         {
             id1 = 0;
         }
         else
         {
             id1 = Convert.ToInt32(dataGridView1.Rows[e.RowIndex].Cells["id"].Value.ToString());
         }

         if (id1 == 0)
         {
             SqlCommand cmd = con.CreateCommand();
             cmd.CommandType = CommandType.Text;
             cmd.CommandText = "Insert into DBTable values('" + dataGridView1.Rows[e.RowIndex].Cells["FileName"].Value.ToString() + "','" + dataGridView1.Rows[e.RowIndex].Cells["Sequence"].Value.ToString() + "','" + dataGridView1.Rows[e.RowIndex].Cells["Delay"].Value.ToString() + "')";
             cmd.ExecuteNonQuery();
             Fill_grid();
         }

         else
         {
             SqlCommand cmd = con.CreateCommand();
             cmd.CommandType = CommandType.Text;
             cmd.CommandText = "update DBTable set Filename='" + dataGridView1.Rows[e.RowIndex].Cells["Filename"].Value.ToString() + "',Sequence='" + dataGridView1.Rows[e.RowIndex].Cells["Sequence"].Value.ToString() + "',Delay='" + dataGridView1.Rows[e.RowIndex].Cells["Delay"].Value.ToString() + "' where id=" + id1 + "";
             cmd.ExecuteNonQuery();
             Fill_grid();

         }

     }