[英]Binding of TextBlock inside Custom Control to dependency property of the same Custom Control
[英]Binding to a dependency property of a behavior inside a child control
我有以下带有自定义依赖项属性的用户控件
ThumbnailListView用户控件
<ListView
ItemsSource="{Binding}"
BorderThickness="0,0,0,0"
HorizontalAlignment="Center"
Background="White"
SelectionChanged="ListView_SelectionChanged"
AllowDrop="True">
<i:Interaction.Behaviors>
<behaviors:DragDropBehavior OnDragDrop="{Binding Path=ItemDragDrop}"></behaviors:DragDropBehavior>
</i:Interaction.Behaviors>
<ListView.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}">
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Converter={StaticResource IsLastListItem}}" Value="False">
<Setter Property="Margin" Value="0,0,0,20"></Setter>
</DataTrigger>
</Style.Triggers>
<Setter Property="Background" Value="Gray"></Setter>
<Setter Property="IsSelected" Value="{Binding Path=IsSelected, Mode=TwoWay}"></Setter>
</Style>
</ListView.ItemContainerStyle>
<ListView.ItemTemplate>
<DataTemplate>
<Image Source="{Binding Thumbnail, Converter={StaticResource ImageConverter}}"></Image>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
ThumbnailListView的依赖项属性ItemDragDrop
public static ICommand GetItemDragDrop(DependencyObject obj)
{
return (ICommand)obj.GetValue(ItemDragDropProperty);
}
public static void SetItemDragDrop(DependencyObject obj, ICommand value)
{
obj.SetValue(ItemDragDropProperty, value);
}
public static DependencyProperty ItemDragDropProperty = DependencyProperty.RegisterAttached("ItemDragDrop",
typeof(ICommand), typeof(ThumbnailListView));
public ICommand ItemDragDrop
{
get
{
return (ICommand)GetValue(ItemDragDropProperty);
}
set
{
SetValue(ItemDragDropProperty, value);
}
}
NewScansView用户控件
<DockPanel Dock="Top">
<ListView ItemsSource="{Binding Scans}" Width="500">
<ListView.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Caption}" Margin="5,0,0,0"></TextBlock>
</DataTemplate>
</ListView.ItemTemplate>
<ListView.ItemContainerStyle>
<Style TargetType="{x:Type ListViewItem}">
<Setter Property="IsSelected" Value="{Binding Path=IsSelected, Mode=TwoWay}"/>
</Style>
</ListView.ItemContainerStyle>
</ListView>
<Views:ThumbnailListView DataContext="{Binding SelectedItem.Pages}" ItemDragDrop="{Binding SelectedItem.DragDropCommand}" VerticalAlignment="Stretch" Width="200" />
<Views:PageListView DataContext="{Binding SelectedItem.Pages}" VerticalAlignment="Stretch" />
</DockPanel>
NewScansView xaml包含一个ThumbnailListView控件,并将ThumbnailListView的依赖项属性ItemDragDrop绑定到SelectedItem类中的命令。
在ThumbnailListView用户控件内部,我有一个行为DragDropBehavior,它具有依赖项属性OnDragDrop。
我试图将OnDragDrop绑定到ItemDragDrop,以便在拖放操作完成时执行SelectedItem类中的命令。
问题在于,它似乎无法在ThumbnailListView上找到ItemDragDrop属性或所选项目类的DragDropCommand。
我想知道我在做错什么以及如何设置?
ThumbnailListView.DataContext
设置为SelectedItem.Pages
,我高度怀疑SelectedItem.Pages
是否具有名为SelectedItem.DragDropCommand
的属性。
更改ItemDragDrop
绑定的Source
,以指定它使用ThumnailListView.DataContext
以外的其他东西作为该绑定的源。
<DockPanel x:Name="MyDockPanel" Dock="Top">
...
<Views:ThumbnailListView DataContext="{Binding SelectedItem.Pages}"
ItemDragDrop="{Binding SelectedItem.DragDropCommand, ElementName=MyDockPanel}" ... />
...
</DockPanel>
您可能还必须对行为绑定执行相同的操作-更改其源,以使其指向ThumbnailListView
而不是ThumbnailListView.DataContext
<i:Interaction.Behaviors>
<behaviors:DragDropBehavior OnDragDrop="{Binding Path=ItemDragDrop, RelativeSource={RelativeSource AncestorType={x:Type local:ThumbnailListView}}}" />
</i:Interaction.Behaviors>
或者更好的方法是,为Pages制作DependencyProperty,这样您就不必依赖特定的DataContext
对象类型了。
<Views:ThumbnailListView PagesDependencyProperty="{Binding SelectedItem.Pages}" ItemDragDrop="{Binding SelectedItem.DragDropCommand}" .. />
或编辑您的控件,以使其假定某个特定类型用于DataContext,并使用隐式DataTemplate始终使用此控件绘制该类型的对象(对我而言更常见):
<ListView ItemsSource="{Binding Pages}" ...>
<i:Interaction.Behaviors>
<behaviors:DragDropBehavior OnDragDrop="{Binding DragDropCommand}" />
</i:Interaction.Behaviors>
...
</ListView>
隐式数据模板:
<DataTemplate DataType="{x:Type local:WhateverSelectedItemDataTypeIs}}">
<!-- DataContext will automatically set to WhateverSelectedItemDataTypeIs -->
<Views:ThumbnailListView />
</DataTemplate>
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