我有这需要在其构造两个参数的AccountViewModel
对象:在DataStore
注册WindsorContainer
对象和Account
数据模型对象。
现在,当用户在帐户的列表中选择一个帐户,我需要使用所选择的帐户resolve
从容器AccountViewModel
对象。
但问题是没有在容器中注册的帐号,当我注册它的SelectionChanged
事件,我遇到了一个重复注册错误。
我还调查了不同的生命周期每个依存性,但我仍然无法找出一个解决方案(我显然在使用IoC框架,因为我更喜欢我自己的工厂类初学者)。
保持AccountViewModel
的是,但use a factory for dependency injection:
public interface IAccountViewModelFactory
{
AccountViewModel Create(AccountModel model);
}
然后,您可以执行(和你的DI容器注册)的工厂是这样的:
public class AccountViewModelFactory : IAccountViewModelFactory
{
public AccountViewModelFactory(IAccountService accountService)
{
AccountService = accountService;
}
public IAccountService AccountService { get; }
public AccountViewModel Create(AccountModel model)
{
return new AccountViewModel(AccountService, model);
}
}
假设AccountViewModel
看起来是这样的:
public class AccountViewModel
{
public AccountViewModel(IAccountService accountService, AccountModel model)
{
AccountService = accountService;
Model = model;
}
public IAccountService AccountService { get; }
public AccountModel Model { get; }
}
排除从构造的数据对象,并且经由一个初始化方法传递数据。
public class AccountModel
{
public int Id { get; set; }
// some more properties
}
public interface IAccountService
{
Task<AccountModel> GetByIdAsync(int id);
}
public class AccountViewModel
{
public AccountViewModel(IAccountService accountService)
{
AccountService = accountService;
}
protected IAccountService AccountService { get; }
private Task LoadFromModelAsync(AccountModel model)
{
Id = model.Id;
_originalModel = model;
return Task.CompletedTask;
}
private AccountModel _originalModel;
public int Id { get; private set; }
public async Task InitializeAsync(object parameter)
{
switch (parameter)
{
case null:
await LoadFromModelAsync(new AccountModel());
break;
case int id:
{
var model = await AccountService.GetByIdAsync(id);
await LoadFromModelAsync(model);
break;
}
case AccountModel model:
await LoadFromModelAsync(model);
break;
default:
throw new InvalidOperationException();
}
}
}