WPF MultiBinding - UnsetValue问题 [英] WPF MultiBinding - UnsetValue Issue

问题描述

我有一个TextBlock。当它的文本绑定为：

I have a TextBlock. When its Text is bound as:

<Binding Path="Applicant2.Surname"/>

它工作得很好，不过，我想包括Forenames改变，以便结合：

It works fine, however I want to include the Forenames so changed the binding to:

<MultiBinding StringFormat="{}{0} {1}">
    <Binding Path="Applicant2.Forenames"/>
    <Binding Path="Applicant2.Surname"/>
</MultiBinding>

这显示{DependencyProperty.UnsetValue} {} DependencyProperty.UnsetValue直到值设置的第一次。

This displays {DependencyProperty.UnsetValue} {DependencyProperty.UnsetValue} until the value is set the first time.

我怎样才能停止？为什么我不能与第一个简单绑定的问题？

How can I stop this? Why do I not get the problem with the first simple binding?

推荐答案

对于multibinding你需要添加一个备用的值，如果它仅仅是空白的，那么你可以简单地做：

for a multibinding you need to add a fallback value if it is just blank then you can simply do:

<MultiBinding StringFormat="{}{0} {1}">
    <Binding Path="Applicant2.Forenames" FallbackValue=""/>
    <Binding Path="Applicant2.Surname" FallbackValue=""/>
</MultiBinding>

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