private void okButton_Click(object sender, RoutedEventArgs e)
        {
            if (validateFields())
            {
                string   name      = animalName.Text;
                string   regCode   = registryCode.Text;
                int      kindId    = (int)animalKindId.SelectedValue;
                DateTime birthDate = (DateTime)animalBirthDate.SelectedDate;
                Sex      sex       = (Sex)animalSex.SelectedItem;
                int      rationId  = (int)ration.SelectedValue;

                //if(vm.AddAnimal(name, regCode, birthDate, kindId, sex, rationId))
                if (vm.Create(new Animal(name, regCode, kindId, birthDate, sex, rationId)))
                {
                    this.Close();
                }
                else
                {
                    MessageBox.Show("Животное с таким регистрационным кодом уже существует!");
                }
            }
        }