Xamly确定ListBox.Items.Count是否> 0

Question

在XAML中是否有办法确定ListBox是否有数据？

如果没有数据,我想将其IsVisibile属性设置为false.

Answer 1

ListBox包含您可以绑定的HasItems属性.所以你可以这样做:

<BooleanToVisibilityConverter x:Key="BooleanToVisibility" />
...
<ListBox 
    Visibility="{Binding HasItems, 
      RelativeSource={RelativeSource Self}, 
      Converter=BooleanToVisibility}" />

或者作为触发器,因此您不需要转换器:

<ListBox>
  <ListBox.Style>
    <Style TargetType="{x:Type ListBox}">
      <Setter Property="Visibility" Value="Visible" />
      <Style.Triggers>
        <DataTrigger 
            Binding="{Binding HasItems, RelativeSource={RelativeSource Self}}"
            Value="False">
          <Setter Property="Visibility" Value="Hidden" />
        </DataTrigger>
      </Style.Triggers>
    </Style>
  </ListBox.Style>
</ListBox>

我没有测试绑定,所以可能会有一些错别字,但你应该明白这个想法.

Answer 2

在触发器中执行它并且您不需要ValueConverter:

<ListBox>
  <ListBox.Style>
    <Style TargetType="{x:Type ListBox}">
      <Style.Triggers>
        <DataTrigger 
          Binding="Items.Count, {Binding RelativeSource={RelativeSource Self}}"
          Value="0">
          <Setter Property="Visibility" Value="Hidden" />
        </DataTrigger>
      </Style.Triggers>
    </Style>
  </ListBox.Style>
</ListBox>

因此默认显示ListBox,但如果Items.Count为0,则ListBox将被隐藏.