you can use given Command Format to save your Data using Datatable.
SqlCommand cmd = new SqlCommand("Command ", Connection);
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = cmd;
SqlCommandBuilder cmdbuilder = new SqlCommandBuilder(da);
DataSet ds = new DataSet();
da.Fill(ds, "TableName");
DataTable dt = ds.Tables["TableName"];
DataRow dr = dt.NewRow();
dr[index] = textbox1.Text;
dr[index] = textbox2.Text;
dt.Rows.Add(dr);
da.Update(ds, "TableName");