MVVM Light的異步綁定問題

Question

我想用MVVM Light將數據綁定到網格。如果我做了以下工作原理：

public class GuidePageViewModel : ViewModelBase 
{ 
    private ObservableCollection<SimpleChannelData> _simpleChannelDataList; 
    private IChannelDataService _channelDataService; 

    public GuidePageViewModel(IChannelDataService channelDataService) 
    { 
     _channelDataService = channelDataService; 

     ATest(); // Create data synchronously here 
    } 

    private void ATest() 
    { 
     SimpleChannelDataList = new ObservableCollection<SimpleChannelData>(); 

     var record = new SimpleChannelData() 
     { 
      Cn = 120, 
      Csign = "Hey", 
      Hd = "Y", 
      Index = 1, 
      Premium = "y", 
      TrbId = 9 
     }; 

     SimpleChannelDataList.Add(record); 
    } 

    private async void Start() 
    { 
     await LoadChannelData(); 
    } 

    private async Task LoadChannelData() 
    { 
     SimpleChannelDataList = new ObservableCollection<SimpleChannelData>((await _channelDataService.GetChannelData())); 
     RaisePropertyChanged(() => SimpleChannelDataList); 
    } 

    #region Public Properties 

    public ObservableCollection<SimpleChannelData> SimpleChannelDataList 
    { 
     get 
     { 
      return _simpleChannelDataList; 
     } 
     set 
     { 
      if (Set(() => SimpleChannelDataList, ref _simpleChannelDataList, value)) 
      { 
       RaisePropertyChanged(() => SimpleChannelDataList); 
      } 

     } 
    } 
    #endregion 
} 

現在，如果我改變的構造，而不是下面，使用異步調用Start，電網沒有得到數據：

public GuidePageViewModel(IChannelDataService channelDataService) 
{ 
    _channelDataService = channelDataService; 
    Start(); 
} 

我知道這是某種異步問題，但我無法弄清楚。有人能指出我做錯了什麼嗎？

Answer 1

起初，您不應該在constructor中調用異步方法。嘗試改變你的邏輯，以便不需要該呼叫。

與此同時，請嘗試檢查AsyncMVVM。它包含一些有趣的模式，以異步方式檢索數據，同時公開常見的MVVM界面。