public void SaveContactperson()
        {
            try
            {
                string sql = "INSERT INTO Contactpersonen(Name, FirstName, Gender, Birthdate, Company, Street,City,Phone,Cellphone,Email,ContactpersoontypeID,Number) ";
                sql += "VALUES (@Name,@FirstName,@Gender,@Birthdate,@Company,@Street,@City,@Phone,@Cellphone,@Email,@JobRole,@Number)";
                DbParameter parName      = Database.AddParameter("@Name", SelectedContactperson.Name);
                DbParameter parFirstName = Database.AddParameter("@FirstName", SelectedContactperson.FirstName);
                DbParameter parGender    = Database.AddParameter("@Gender", SelectedContactperson.Gender);
                DbParameter parBirthdate = Database.AddParameter("@Birthdate", SelectedContactperson.BirthDate);
                DbParameter parCompany   = Database.AddParameter("@Company", SelectedContactperson.Company);
                DbParameter parStreet    = Database.AddParameter("@Street", SelectedContactperson.Street);
                DbParameter parCity      = Database.AddParameter("@City", SelectedContactperson.City);
                DbParameter parPhone     = Database.AddParameter("@Phone", SelectedContactperson.Phone);
                DbParameter parCellphone = Database.AddParameter("@Cellphone", SelectedContactperson.Cellphone);
                DbParameter parEmail     = Database.AddParameter("@Email", SelectedContactperson.Email);
                DbParameter parNumber    = Database.AddParameter("@Number", SelectedContactperson.Number);
                DbParameter parJobRole   = Database.AddParameter("@JobRole", SelectedContactperson.JobRole.ID);

                Database.ModifyData(sql, parName, parFirstName, parGender, parBirthdate, parCompany, parStreet, parCity, parPhone, parCellphone, parEmail, parNumber, parJobRole);
                ContactpersonList.Add(SelectedContactperson);
                ContactpersonList = Contactperson.GetContactpersons();
                MessageBox.Show("Contactpersoon werd succesvol toegevoegd");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
 public void DeleteContactperson()
 {
     if (SelectedContactperson != null)
     {
         try
         {
             string      sql = "DELETE FROM contactpersonen WHERE ID=@id";
             DbParameter par = Database.AddParameter("@id", SelectedContactperson.ID);
             Database.ModifyData(sql, par);
             ContactpersonList.Remove(SelectedContactperson);
             MessageBox.Show("Contactpersoon werd succesvol verwijderd");
         }
         catch (Exception ex)
         {
             MessageBox.Show(ex.Message);
         }
     }
 }