The question is: Why does this not create a new row?

What am I forgetting/doing wrong?

Code:
DataRow newGuestRow = guestsDataSet.Tables["Guests"].NewRow();

newGuestRow["FirstName"] = txtFirstName.Text;
newGuestRow["LastName"] = txtLastName.Text;
newGuestRow["Destination"] = txtDestination.Text;
newGuestRow["Other Comments"] = txtOtherInfo.Text;

guestsDataSet.Tables["Guests"].Rows.Add(newGuestRow);