我需要一些帮助来理解如何实例化ViewModels而不将它们全部作为MainViewModel类构造函数的参数。
你们中是否有人能够帮助我理清思路并摆脱在构造函数中添加许多参数的情况。我已经阅读了关于工厂模式的文章,但我不知道如何实现它,或者也许那不是解决方案?无论如何,以下是代码。
谢谢。请帮帮我,这让我发疯了!
app.xaml.cs
private readonly ServiceProvider _serviceProvider;
public App()
{
ServiceCollection services = new ServiceCollection();
ConfigureServices(services);
_serviceProvider = services.BuildServiceProvider();
}
private void ConfigureServices(ServiceCollection services)
{
services.AddSingleton<MainWindow>();
// Services
services.AddSingleton<ICustomerService, CustomerService>();
// ViewModels
services.AddScoped<MainViewModel>();
services.AddScoped<CustomerViewModel>();
services.AddScoped<CustomerAddViewModel>();
services.AddScoped<CustomerEditViewModel>();
services.AddScoped<ServiceViewModel>();
}
private void OnStartup(object sender, StartupEventArgs e)
{
var mainWindow = _serviceProvider.GetService<MainWindow>();
mainWindow.DataContext = _serviceProvider.GetService<MainViewModel>();
mainWindow.Show();
}
MainViewMode.cs
public class MainViewModel : ViewModelBase
{
private CustomerViewModel _customerViewModel;
private CustomerAddViewModel _customerAddViewModel;
private CustomerEditViewModel _customerEditViewModel;
private ViewModelBase _selectedViewModel;
public ViewModelBase SelectedViewModel
{
get => _selectedViewModel;
set
{
_selectedViewModel = value;
NotifyPropertyChanged();
}
}
public RelayCommand CustCommand { get; set; }
public RelayCommand ServCommand { get; set; }
**public MainViewModel(
CustomerViewModel customerViewModel,
CustomerAddViewModel customerAddViewModel,
CustomerEditViewModel customerEditViewModel)
{
_customerViewModel = customerViewModel;
_customerAddViewModel = customerAddViewModel;
_customerEditViewModel = customerEditViewModel;
CustCommand = new RelayCommand(OpenCustomer);
}**
private void OpenCustomer()
{
SelectedViewModel = _customerViewModel;
}
}
客户视图模型
public class CustomerViewModel : ViewModelBase
{
private ICustomerService _repo;
private ObservableCollection<Customer> _customers;
public ObservableCollection<Customer> Customers
{
get => _customers;
set
{
_customers = value;
NotifyPropertyChanged();
}
}
public CustomerViewModel(ICustomerService repo)
{
_repo = repo;
}
public async void LoadCustomers()
{
List<Customer> customers = await _repo.GetCustomers();
Customers = new ObservableCollection<Customer>(customers);
}
}