WPF 绑定(bind) FallbackValue 设置为绑定(bind)

Question

有没有办法将另一个绑定(bind)作为后备值？

我正在尝试做这样的事情:

<Label Content="{Binding SelectedItem.Name, ElementName=groupTreeView,
                         FallbackValue={Binding RootGroup.Name}}" />

如果有人有另一个技巧来实现它，那就太好了。

Answer 1

您正在寻找的是称为 PriorityBinding 的东西(this 列表中的#6)

(来自文章)

The point to PriorityBinding is to name multiple data bindings in order of most desirable to least desirable. This way if the first binding fails, is empty and/or default, another binding can take it's place.

例如

<TextBox>
    <TextBox.Text>
        <PriorityBinding>
            <Binding Path="LastNameNonExistant" IsAsync="True" />
            <Binding Path="FirstName" IsAsync="True" />
        </PriorityBinding>
    </TextBox.Text>
</TextBox>