private void btnAdd_Click(object sender, EventArgs e)
{
CustomerCounty _newRecord = new CustomerCounty();
_newRecord.CustomerId = this.CustomerId;
_newRecord.CountyCode = (int)cboCountys.SelectedValue;
_newRecord.CountyDescription = cboCountys.Text;
_db.AddToCounties(_newRecord);
_db.SaveChanges();
this.Close();
}