Question

在Universal Windows App风格的Xaml中，我想创建一个具有非常相似的附加属性的自定义面板，例如Canvas.Left（或Top，Right或Bottom）。所以我可以根据guide

创建一个

public static readonly DependencyProperty XProperty = 
    DependencyProperty.RegisterAttached("X", typeof(double), typeof(Track), null);

public static double GetX(DependencyObject d)
{
   return (double)d.GetValue(XProperty);
}
// SetX and property wrapper omitted for brevity here

现在我可以写

了

<c:Track>
  <TextBlock Text="1" c:Track.X="1"/>
  <TextBlock Text="2" c:Track.X="2"/>
  <TextBlock Text="3" c:Track.X="3"/>
</c:Track>

然后我可以在

中使用我附加的值

public override void ArrangeOverride(Size finalSize)
{
  foreach (var child in Children)
  { 
     var x = GetX(child);
     child.Arrange(CalculateArrange(x, finalSize));
  }
}

到目前为止，一切都运转良好。

但是，当我们来到ItemsControl时，我可以这样做，

<ItemsControl ItemsSource="{Binding ListOfInts}">
  <ItemsControl.ItemPanel>
    <ItemPanelTemplate>
       <Canvas/>
    </ItemPanelTemplate>
  </ItemsControl.ItemPanel>

  <ItemsControl.ItemTemplate>
    <DataTemplate x:DatatType="Int">
      <TextBlock Canvas.Left="{Binding}" Text="{Binding}"/>
    </DataTemplate>
  </ItemsControl.ItemTemplate>
</ItemsControl>

但如果我想为我自己的自定义面板做这件事，我必须这样做

<ItemsControl ItemsSource="{Binding ListOfInts}">
  <ItemsControl.ItemPanel>
    <ItemPanelTemplate>
       <Track/>   <!--Change to my panel-->
    </ItemPanelTemplate>
  </ItemsControl.ItemPanel>

 <ItemsControl.ItemContainerStyle>  <!-- need to add the attached property here -->
   <Style TargetType="ContentPresenter">
     <Setter Property="c:Track.X" Value="{Binding}"/>
   </Style>
 </ItemsControl.ItemContainerStyle>

  <ItemsControl.ItemTemplate>
    <DataTemplate x:DatatType="Int">
      <TextBlock Text="{Binding}"/>
    </DataTemplate>
  </ItemsControl.ItemTemplate>
</ItemsControl>

因为我做不到

public override void ArrangeOverride(Size finalSize)
{
  //Children are now contentPresenters
  foreach (ContentPresenter child in Children) 
  {
    var controlWithAttribute = child.????
    //child.Content is the same as DataContext i.e. an Int

    var x = GetX(controlWithAttribute);
    child.Arrange(CalculateArrange(, finalSize));
  }
}

我缺少什么想法？如何让ItemsControl与Canvas.Left一样工作？

自定义附加属性不像Canvas.Left

0 个答案: