带有空项目的组合框? [英] ComboBox with empty item?

问题描述

假设我们有一个 DataSource 绑定到一个来自 Database 的集合.当然没有空项目.如何将 void 项添加到 ComboBox，以便在第一次加载时用户会看到一个空字符串.我不想在集合中添加一个虚拟/空对象.最好在 XAML 中.有什么建议吗?

Suppose we have a DataSource bind to a collection from Database. There is no null item of course. How to add a void item into a ComboBox, so that at first load user would see an empty string. I don't want to add a dummy/void object into the Collection. Optimally in XAML. Any proposals?

推荐答案

<ComboBox Name="myComboBox" Width="200" Background="White">    
    <ComboBox.ItemsSource>    
        <CompositeCollection>
           <ComboBoxItem IsEnabled="False" Foreground="Black">Select Item</ComboBoxItem>
           <CollectionContainer Collection="{Binding Source={StaticResource DataKey}}" />    
        </CompositeCollection>
    </ComboBox.ItemsSource>
</ComboBox>

编辑

正如评论中提到的 @surfen，BindingProxy 是绑定问题的解决方法

As @surfen mentioned in comment, BindingProxy is workaround for the binding issue

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