how to insert dynamically datagridview data to database

int sitting = Convert.ToInt32(D3.Text);
 DataTable dt = new DataTable();
 DataRow dr;
 dt.Column1.Add("Treatment Name");
 dt.Columns.Add("Detail");
dt.Columns.Add("amount");
for (int i = 0; i < sitting; i++)
{
 dr = dt.NewRow();

 dr["Treatment Name"] = D1.Text;
    dr["Detail"] = D2.Text;
   dr["amount"] = "";
   dt.Rows.Add(dr);
   }
  dataGridView1.DataSource = dt;