Question

我正在尝试使用以下功能创建“ModalPopup”自定义控件：

它始终显示主内容区Content。
它有一个子PopupItems项集合，在主要内容区域的顶部显示（模态），并带有覆盖主要内容区域的半透明边框。
如果任何子项目的IsShown属性设置为true，则会显示它们，并且将禁用主要内容区域。

我已经让这个工作了，但我一直在设计器中遇到错误A value of type ‘ModalPopupItem’ cannot be added to a collection or dictionary of type ‘ObservableCollection’.我尝试过使用UIElementCollection，List，List，但我仍然遇到错误。在重新编译之前，Designer也没有反映我对xaml所做的任何更改，这非常令人沮丧。

如何让设计师停止出现这些错误？

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);
             }
    }

资源文件：

   <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>

这就是我的控件的使用方式......

  <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>

带子项的Wpf自定义控件

0 个答案: