在 wpf 中禁止/阻止选择禁用的组合框项目 [英] Disallow/Block selection of disabled combobox item in wpf

问题描述

我正在编写一个应用程序，其中我想禁用 ComboBox 中的几个项目，并且还想禁止/阻止选择禁用的项目.请注意主窗口中的 ComboBox 有另一个 ComboBox 作为 ComboBox Item init(由数据模板选择器在运行时决定).

I'm writing an application wherein I would like to disable few items in the ComboBox and also want to disallow/block selection of disabled items. Please note ComboBox in main window has another ComboBox as ComboBox Item init (that is decided at run time by data template selector).

使用下面的代码，我可以禁用 ComboBox 中的 ComboBox，但它不会阻止用户选择该禁用的 ComboBox 项目.任何有关禁止/阻止选择禁用项目的帮助都会有所帮助.

With below code I'm able to disable a ComboBox within ComboBox but it would not stop user from selecting that disabled ComboBox item. Any help in disallow/block selection of disabled items would be helpful.

以下是代码片段

主窗口中的组合框:

<Grid>
    <ComboBox HorizontalAlignment="Left" VerticalAlignment="Top" 
              Width="120" Margin="87.2,44.8,0,0" 
              ItemsSource="{Binding Cars}" 
              ItemsPanel="{DynamicResource ItemsPanelTemplateHorizontal}"
              ItemTemplateSelector="{StaticResource QualityComboBoxTemplateSelector}"
              SelectedItem="{Binding SelectedItm}"/>
</Grid>

数据模板选择器:

public class QualityComboBoxTemplateSelector : DataTemplateSelector
{
    public override DataTemplate SelectTemplate(object item, DependencyObject container)
    {
        var element = container as FrameworkElement;

        var dataTemplate = element.FindResource(((item is string) && item.Equals("Ferrari")) ?
                                                       "DataTemplateTopLevelCombobox2" : "DataTemplateTopLevelCombobox1") as DataTemplate;

        return dataTemplate;
    }
}

上述组合框的数据模板:

<DataTemplate x:Key="DataTemplateTopLevelCombobox1">
    <Border BorderBrush="Black" BorderThickness="1" >
        <TextBlock HorizontalAlignment="Left" 
                   TextWrapping="Wrap" Text="{Binding}"     
                   VerticalAlignment="Top"/>
    </Border>
</DataTemplate>

<DataTemplate x:Key="DataTemplateTopLevelCombobox2">
    <Border Width="100">
        <ComboBox Text="Custom" Height="21.96"
        ItemsSource="{Binding DataContext.Models, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}"
        IsEnabled="{Binding DataContext.EnableCombo, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}" />
    </Border>
</DataTemplate>

推荐答案

您可以通过将 ComboBoxItem 的 IsEnabled 属性设置为 false 来实现此目的>;

You can achieve this by setting IsEnabled property of a ComboBoxItem to false;

所以 ComboBox 的 ItemSource(即 Cars 在你的例子中)中的每个项目都可以是一个具有某些属性(比如 IsSelectable)的对象，指定是否应该启用或禁用它，然后将其与样式一起使用以使项目不可选择.像这样 -

So each item in ComboBox's ItemSource (i.e. Cars in your case) can be an object having some property (say IsSelectable) specifying whether it should be enabled or disabled and then use it with a style to make an item un-selectable. something like this -

<Style TargetType="ComboBoxItem"> 
   <Setter Property="IsEnabled" Value="{Binding IsSelectable}"/> 
</Style> 

更新:

<Grid>
    <ComboBox
        Width="120"
        Margin="87.2,44.8,0,0"
        HorizontalAlignment="Left"
        VerticalAlignment="Top"
        ItemTemplateSelector="{StaticResource QualityComboBoxTemplateSelector}"
        ItemsPanel="{DynamicResource ItemsPanelTemplateHorizontal}"
        ItemsSource="{Binding Cars}"
        SelectedItem="{Binding SelectedItm}">
        <ComboBox.ItemContainerStyle>
            <Style TargetType="ComboBoxItem">
                <Setter
                    Property="IsEnabled"
                    Value="{Binding IsSelectable}" />
            </Style>
        </ComboBox.ItemContainerStyle>
    </ComboBox>
</Grid>

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