WPF自定義控件與兒童項目

我試圖創建一個「ModalPopup」自定義控制，具有以下特點：WPF自定義控件與兒童項目

它有一個主要內容區Content是始終顯示。
它有一個子集合PopupItems項目（模態地）顯示在主內容區域頂部，半透明邊框覆蓋主內容區域。
如果有任何子項目的IsShown屬性設置爲true，則會顯示它們，主內容區域將被禁用。

我已經得到這個工作，但我不斷收到錯誤，像A value of type ‘ModalPopupItem’ cannot be added to a collection or dictionary of type ‘ObservableCollection’.我使用UIElementCollection，列表，列表嘗試了設計師，我仍然不斷收到錯誤。此外，設計者並沒有反映我對xaml所做的任何更改，直到我重新編譯，這是非常令人沮喪的。

我能做些什麼來讓設計師停止發生這些錯誤？

ModalPopup：

public class ModalPopup: ContentControl 
    { 
     public ModalPopup() 
     { 
      this.PopupItems = new ObservableCollection<ModalPopupItems>(); 
      this.Loaded += ModalPopup_Loaded; 
     } 

     private void ModalPopup_Loaded(object sender, RoutedEventArgs e) 
     { 
      foreach (ModalPopupItem item in this.PopupItem) 
      { 
       Item.IsShownChanged += Item_IsShownChanged; 
      } 
      UpdateOverlay(); 
     } 

     public static readonly DependencyProperty ShowOverylayProperty = 
     DependencyProperty.Register.(「ShowOverlay」, typeof(bool), typeof(ModalPopup), new PropertyMetadata(true)); 
     public bool ShowOverlay 
     { 
      get {return (bool)GetValue(ShowOverlayProperty);} 
      set {SetValue(ShowOverlayProperty, value);} 
     } 

     public static readonly DependencyProperty PopupItemsProperty = 
     DependencyProperty.Register.(「PopupItems」, typeof(ObservableCollection<ModalPopupItem>), typeof(ModalPopup)) 
     public ObservableCollection<ModalPopupItem>ShowOverlay 
     { 
      get {return (ObservableCollection<ModalPopupItem>)GetValue(ShowOverlayProperty);} 
      set {SetValue(ShowOverlayProperty, value);} 
     } 

     private void UpdateOverlay() 
     { 
      ShowOverlay = (PopupItems?.Any(item => item.IsShown) ?? false); 
     } 

     private void item_IsShownChanged(object sender, EventArgs e) 
     { 
      UpdateOverlay(); 
     } 
    }

ModalPopupItem：

public class ModalPopupItem: ContentControl 
    { 
      public EventHandler IsShownChanged; 

      public static readonly DependencyProperty IsShownProperty = 
      DependencyProperty.Register(「IsShown」, typeof(bool), typeof(ModalPopupItem), new PropertyMetadata(true, IsShownChanged_Callback)); 
      Public bool IsShown 
      { 
        get { return (bool)GetValue(IsShownProperty); } 
        set { SetValue(IsShownProperty, value); } 
      } 

      private static void IsShownChanged_Callback(DependencyObject d, DependencyPropertyChangedEventArgs e) 
      { 
         (d as ModalPopupItem).Visibility = (bool)e.NewValue ? Visibility.Visible : Visibility.Collapsed; 
         (d as ModalPopupItem).IsShownChanged?.Invoke(d, EventArgs.Empty); 
      } 
    }

資源文件：

<Style TargetType=」local:ModalPopup」> 
      <Style.Setters> 
       <Setter Property="Template"> 
        <Setter.Value> 
          <ControlTemplate TargetType="local:ModalPopup"> 
           <Grid> 
            <ContentPresenter Content="TemplateBinding Content}" 
                IsEnabled="{TemplateBinding ShowOverlay, Converter={StaticResource InvertBool}}" /> 
            <ContentControl Template="{StaticResource PopupTemplate}" 
                Visibility="{TemplateBinding ShowOverlay, Converter={StaticResource TrueToVisible}}"> 
             <ItemsControl ItemsSource="{TemplateBinding PopupItems}" /> 
            </ContentControl> 
          </ControlTemplate> 
        </Setter.Value> 
       </Setter> 
      </Style.Setters> 
    </Style>

這是我如何使用我的控制...。

<local:ModalPopup> 
     <!-- Main Content Area --> 
     <TextBlock Text="Main Content" Height=「200」 Width=」200」 /> 

     <!-- Popup Items --> 
     <local:ModalPopup.PopupItems> 
      <local:ModalPopupItem IsShown="False">Popup 1</ local:ModalPopupItem> 
      <local:ModalPopupItem IsShown="True">Popup 2</ local:ModalPopupItem> 
      <local:ModalPopupItem IsShown="{Binding ShowPopup3}">Popup 3</ local:ModalPopupItem> 
     </local:ModalPopup.PopupItems> 
    </local:ModalPopup>

來源

2016-01-18 NuclearProgrammer