如果基础 DataContext 为空，如何隐藏控件? [英] How to hide a control if the underlying DataContext is null?

问题描述

我的视图模型中有一个对象，它有一堆属性，其中一些偶尔会为空.如果这些特定控件为空，我不想只显示一些控件.如果绑定为空，我将如何隐藏控件?我正在考虑某种转换器，但不知道我将如何去做.有什么想法吗?

I have an object in my view model that has a bunch of properties, some of them will occasionally be null. I don't want to just show some controls if these particular controls are null. How would I go about hiding the control if the bind is null? I was thinking of some sort of converter, but don't know how I'd go about doing it exactly. Any ideas?

抱歉，我应该提到这也将在 Silverlight 中，所以我不确定样式触发器是否会起作用......?

edit: sorry, I should mention that this will also be in Silverlight, so I'm not sure if Style triggers would work...?

推荐答案

有一个如下的转换器，

public sealed class NullToVisibilityConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return value == null ? Visibility.Hidden: Visibility.Visible;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

现在，将该属性也与 Visibility 属性绑定.喜欢，

Now, bind the property with the Visibility property as well. Like,

<ListBox ItemsSource="{Binding Path=Squad}" 
         Visibility="{Binding Converter={StaticResource nullToVisibilityConverter}, 
                              Path=Squad}">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <CheckBox Content="{Binding}" />
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

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