禁用基于ObservableCollection的MenuItem是否为空

Question

如果ObservableCollection绑定到ItemsSourcea MenuItem的空是否为空,我如何签入Xaml ？基于此我想启用或禁用MenuItem.

什么是期望的:

<MenuItem 
    ItemsSource="{Binding loadables}" 
    Tag="{Binding load}">
    <MenuItem.Triggers>
        <Trigger Property="HasItems" Value="False">
            <Setter Property="IsEnabled" Value="False"/>
        </Trigger>
    </MenuItem.Triggers>
</MenuItem>

Answer 1

你可以在loadables.Count0 时触发

<MenuItem ItemsSource="{Binding loadables}" Tag="{Binding load}">
    <MenuItem.Style>
        <Style TargetType="{x:Type MenuItem}">
            <Style.Triggers>
                <DataTrigger Binding="{Binding loadables.Count}" Value="0">
                    <Setter Property="IsEnabled" Value="False"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </MenuItem.Style>
</MenuItem>