解决wpf，caliburn.micro框架，重复切换至某个ContentControl后，该界面所有绑定事件突然无效问题

很奇怪的问题，原因不明，多见于 <ContentControl Grid.Row="3" Grid.Column="2" cal:View.Model="{Binding Content}"/> 此种绑定场景下，对Content进行不同viewmodel的赋值，来达到切换界面内容的目的

解决办法：

换个思路，创建ItemsControl，包含所有要使用的子控件，使其中需要显示（激活）的子控件显示，其他则隐藏

View：

<ItemsControl Grid.Row="3" Grid.Column="2" ItemsSource="{Binding Items}" Focusable="False" Height="{Binding ElementName=MainParent,Path=ActualHeight}" Width="{Binding ElementName=MainParent,Path=ActualWidth}">
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <VirtualizingStackPanel VirtualizingStackPanel.VirtualizationMode="Recycling" IsVirtualizing="True" VirtualizingPanel.ScrollUnit ="Pixel"/>
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <ContentControl cal:View.Model="{Binding IsAsync=True}">
                <ContentControl.Visibility>
                    <MultiBinding Converter="{StaticResource MultiCompareToVisibilityConverter}">
                        <Binding />
                        <Binding Path="DataContext.ActiveItem" RelativeSource="{RelativeSource AncestorType={x:Type ItemsControl}}"/>
                    </MultiBinding>
                </ContentControl.Visibility>
            </ContentControl>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

ViewModel：

基类：

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

public abstract class ActiveViewModel : BaseViewModel {     /// <summary>     /// 设置显示页面     /// </summary>     /// <param name="screen"></param>     /// <returns></returns>     public Task SetActiveItem(Caliburn.Micro.Screen screen = null)     {         if (this.ActiveItem == screen)             return Task.Run(() => this.Get<MainViewModel>().IsBusy = false);         else             return Task.Run(async () => await this.ActivateItemAsync(screen)).ContinueWith(__ =>                  this.Get<MainViewModel>().IsBusy = false);     } }

　

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118

public class BaseViewModel : Conductor<object>.Collection.OneActive {     #region private fields     /// <summary>     /// 窗体管理器     /// </summary>     protected readonly IWindowManager windowManager;     #endregion       #region consturtor     static BaseViewModel()     {         // Caliburn.Micro(CM) 穿过 Popup 绑定方法 http://www.cnblogs.com/gaoshang212/p/4203929.html         ActionMessage.SetMethodBinding = context =>         {             var source = context.Source;             System.Windows.DependencyObject currentElement = source;             while (currentElement != null)             {                 if (Caliburn.Micro.Action.HasTargetSet(currentElement))                 {                     var target = Message.GetHandler(currentElement);                     if (target != null)                     {                         var method = ActionMessage.GetTargetMethod(context.Message, target);                         if (method != null)                         {                             context.Method = method;                             context.Target = target;                             context.View = currentElement;                             return;                         }                     }                     else                     {                         context.View = currentElement;                         return;                     }                 }                   //修改部分 Begin                 var pElement = System.Windows.Media.VisualTreeHelper.GetParent(currentElement);                 if (pElement == null                     && currentElement.GetType().Name.Equals("PopupRoot", System.StringComparison.OrdinalIgnoreCase))                 {                     if (currentElement is System.Windows.FrameworkElement ef)                         pElement = ef.Parent;                 }                   currentElement = pElement;                 //End             }               if (source != null && source.DataContext != null)             {                 var target = source.DataContext;                 var method = ActionMessage.GetTargetMethod(context.Message, target);                   if (method != null)                 {                     context.Target = target;                     context.Method = method;                     context.View = source;                 }                 else                 {                     source.Visibility = System.Windows.Visibility.Collapsed;                 }             }         };     }     /// <summary>     /// 构造函数     /// </summary>     public BaseViewModel() => this.windowManager = this.Get<IWindowManager>();     /// <summary>     /// 构造函数     /// </summary>     /// <param name="windowManager"></param>     public BaseViewModel(IWindowManager windowManager)     {         this.windowManager = windowManager;     }     #endregion       #region public methods     /// <summary>     /// 根据类型和名称获取实例对象     /// </summary>     /// <typeparam name="T"></typeparam>     /// <param name="name"></param>     /// <returns></returns>     public virtual T Get<T>(string name = null) => (T)IoC.Get<T>(name);       /// <summary>     /// 提示消息     /// </summary>     /// <param name="message">提示内容</param>     /// <param name="isAsk">是否询问消息</param>     /// <returns></returns>     public bool? ShowMessage(string message, MessageType type = MessageType.正常)         => MessageBoxExt.ShowMessage(message, type);       /// <summary>     ///     /// </summary>     /// <param name="viewModel"></param>     /// <returns></returns>     public void ShowWindow(BaseViewModel viewModel, bool dialog = true)     {         if (windowManager==null||viewModel==null) return;         if (dialog)             windowManager.ShowDialogAsync(viewModel);         else             windowManager.ShowWindowAsync(viewModel);     }     #endregion }

　　切换子控件：

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14

……    case ProcessStage.Camera:         if (cameraViewModel==null)             cameraViewModel=this.Get<CameraViewModel>();         this.SetActiveItem(cameraViewModel);         cameraViewModel.StartCamera();         break;     case ProcessStage.Photo:         if (photoViewModel==null)             photoViewModel=this.Get<PhotoViewModel>();         this.SetActiveItem(photoViewModel);         cameraViewModel.StopCamera();         break; ……