WPF的StringFormat上标签内容

问题描述：

我要格式化我的字符串作为金额绑定是X ，其中 X 是绑定到一个标签的属性。

I want to format my string binding as Amount is X where X is a property bound to a label.

我见过很多例子，但下面不工作：

I've seen many examples but the following doesn't work:

<Label Content="{Binding Path=MaxLevelofInvestment, 
   StringFormat='Amount is {0}'}" />

我也试过这些组合：

I've also tried these combinations:

StringFormat=Amount is {0}
StringFormat='Amount is {}{0}'
StringFormat='Amount is \{0\}'

我甚至试图改变绑定属性的数据类型为 INT ，字符串和双。似乎没有任何工作。这是一个很常见的情况，但似乎并没有得到支持。

I even tried changing the binding property's datatype to int, stringand double. Nothing seems to work. This is a very common use case but doesn't seem to be supported.

答

这不起作用的是， Label.Content 属性类型对象和 Binding.StringFormat 绑定到类型的属性时才使用字符串。

The reason this doesn't work is that the Label.Content property is of type Object, and Binding.StringFormat is only used when binding to a property of type String.

正在发生的事情是：

的绑定是拳击您的 MaxLevelOfInvestment 值并将其存储在 Label.Content 属性作为盒装十进制值。

Label控件具有包括内容presenter 。

由于的ContentTemplate 没有设置，内容presenter 寻找一个的DataTemplate为小数定义 键入。当它发现没有，它使用一个默认的模板。

presents字符串使用由内容presenter使用的默认模板标签的 ContentStringFormat 属性。

The Binding is boxing your MaxLevelOfInvestment value and storing it the Label.Content property as a boxed decimal value.
The Label control has a template that includes a ContentPresenter.
Since ContentTemplate is not set, ContentPresenter looks for a DataTemplate defined for the Decimal type. When it finds none, it uses a default template.
The default template used by the ContentPresenter presents strings by using the label's ContentStringFormat property.

两种解决方案：

使用Label.ContentStringFormat代替Binding.StringFormat，或

使用的字符串属性，如TextBlock.Text代替Label.Content

下面是如何使用Label.ContentStringFormat：

Here is how to use Label.ContentStringFormat:

<Label Content="{Binding Path=MaxLevelofInvestment}" ContentStringFormat="Amount is {0}" />

下面是如何使用一个TextBlock：

Here is how to use a TextBlock:

<TextBlock Text="{Binding Path=MaxLevelofInvestment, StringFormat='Amount is {0}'}" />

注：为简单起见，我在上面的解释忽略了一个细节：在内容presenter 实际上使用自己的模板和的StringFormat 属性，但装载这些都是自动模板绑定到的ContentTemplate 和 ContentStringFormat 的标签的属性，所以它好像在内容presenter 实际上是使用标签的属性。

Note: For simplicity I omitted one detail in the above explanation: The ContentPresenter actually uses its own Template and StringFormat properties, but during loading these are automatically template-bound to the ContentTemplate and ContentStringFormat properties of the Label, so it seems as if the ContentPresenter is actually using the Label's properties.

WPF的StringFormat上标签内容

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