我在外部程序集中有服务类,我将这个类注入到带有 MEF 的视图模型类中。我需要从视图模型每 3-4 秒调用一次服务方法。
我从服务中获得新数据作为字典。此字典绑定到视图中的列表框。我需要在视图中刷新这个数据列表框。
在我的解决方案中,我使用 DispatcherTimer,但我绝对是 calibur.micto 以及 MVVM 和 WPF 的初学者。我不知道在我的情况下什么是合适的解决方案。因此,如果有人有进步,我将不胜感激。
我的解决方案在这里:
[Export("MainScreen", typeof(IMainViewModel))]
public class MainViewModel : Screen, IMainViewModel
{
[Import]
private Service _service;//import with MEF from external assembly
[Import]
private Connection _conn;//import with MEF from external assembly
//this dictionary is bind to the listbox in view
private MyObservableDictionary<string, User> _users = null;
//temp dictionry
private MyObservableDictionary<string, User> _freshUsers = null;
private int _selectedUserIndex;
private DispatcherTimer _dispatcherTimer;
public Account Account{ get; set;}
public int SelectedUsersIndex
{
get { return _selectedUserIndex; }
set
{
_selectedUserIndex = value;
NotifyOfPropertyChange("SelectedUsersIndex");
}
}
public MainViewModel()
{
_dispatcherTimer = new DispatcherTimer();
_dispatcherTimer.Tick += DispatcherTimer_Tick;
_dispatcherTimer.Interval = TimeSpan.FromSeconds(3);
_dispatcherTimer.Start();
}
//I get every 3-4 sec from server new JSON data and I need update with this data listbox in view
private void DispatcherTimer_Tick(object sender, EventArgs eventArgs)
{
//server ping, call service method
Account.Ping = _service.Ping(Account);
//Refresh data in dictionary
_freshUsers = _service.LoadUsers(Account);
_users.Clear();
SelectedUsersIndex = 1;
foreach (var freshUser in _freshUsers)
{
_users.Add(freshUser);
}
//check if you have new messanges
if (Account.Ping.Rp > 0)
{
//load new messanges
for (int i = 0; i < Account.Ping.Rp; i++)
{
#region load rp
try
{
Rp message = _service.LoadRp(Account);
if (message != null)
{
//show messages
}
}
catch (Exception exception)
{
if (exception.Message == "You haven’t any messanged")
{
}
throw exception;// how handle show this exception in view?
}
#endregion
}
}
}
}