我有一個(gè)屬性 ( FileName ),當(dāng)我在調(diào)試器中觀察它時(shí)更新得很好(同時(shí)在視圖模型和 XAML 中懸停在屬性上),但 UI 不會(huì)反映值更新。我設(shè)置了一個(gè)斷點(diǎn)set { this.MutateVerbose(ref _fileName, value, RaisePropertyChanged()); },可以觀察它進(jìn)入它并通過RaisePropertyChanged().我通過 將其實(shí)例化為“未更新”的初始值FileName = "Not Updated";,雖然該屬性通過應(yīng)用程序的運(yùn)行持續(xù)時(shí)間成功更新為其他值FileName = SelectRandomString();,但 UI 永遠(yuǎn)不會(huì)更新。相關(guān)界面代碼: <TextBlock Text="{Binding FileName}" HorizontalAlignment="Center"> <TextBlock.DataContext> <ns:ProgressViewModel /> </TextBlock.DataContext> </TextBlock>MutateVerbose 的代碼: public static void MutateVerbose<TField>(this INotifyPropertyChanged instance, ref TField field, TField newValue, Action<PropertyChangedEventArgs> raise, [CallerMemberName] string propertyName = null) { if (EqualityComparer<TField>.Default.Equals(field, newValue)) return; field = newValue; raise?.Invoke(new PropertyChangedEventArgs(propertyName)); }更新:如果我將進(jìn)度計(jì)時(shí)器作為視圖模型加載的一部分啟動(dòng),如下所示: public ProgressViewModel() { KickOffProgressTimer(); }用戶界面按原樣更新。但我不理解這種行為,這是不可取的。我不希望該KickOffProgressTimer();方法在應(yīng)用程序啟動(dòng)后立即執(zhí)行,而是僅在從后面的主窗口代碼中單擊按鈕時(shí)執(zhí)行: private void CircleButtonClick(object sender, RoutedEventArgs e) { ProgressViewModel pvm = new ProgressViewModel(); CircleButton.DataContext = pvm; pvm.KickOffProgressTimer(); }
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TA貢獻(xiàn)1788條經(jīng)驗(yàn) 獲得超4個(gè)贊
您需要指定UpdateSourceTrigger
將觸發(fā) UI 更新的事件:
<TextBlock Text="{Binding FileName, UpdateSourceTrigger=PropertyChanged}" ...
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