WPF的一个小问题 [英] One small question for WPF
问题描述
您好，WPF专家:
< textbox x:name ="textBox1">一些文本</textbox>
"x:"在这里是什么意思，为什么我们在这里需要它?
谢谢！
Hi, WPF experts:
<textbox x:name="textBox1"> some text</textbox>
what does it mean here "x:", why we need it here?
thanks!
推荐答案
来自文档 a> [ ^ ]
为对象元素处理后存在于运行时代码中的实例指定运行时对象名称
From the documentation[^]
Specifies a run-time object name for the instance that exists in run-time code after an object element is processed
请参见:
http://social.msdn.microsoft.com/论坛/da-DK/wpf/thread/216553bf-9be2-4d0a-acc1-b38af8ef948e [
See this:
http://social.msdn.microsoft.com/Forums/da-DK/wpf/thread/216553bf-9be2-4d0a-acc1-b38af8ef948e[^]
如果它是"Key"而不是"x:Key"，则这将要求"Key"成为
在WPF中，这意味着将每个对象添加为资源
需要公开一个名为"Key"的可写DependencyProperty.
这将排除所有不是DependencyObjects的类型，例如字符串或URI或
ViewModels实例-以及所有不具有名为"Key"的DP的实例，
所以只有所有通常用作资源的对象！
使用"x:Key"指令实现时，键不必是
的真实属性
添加的元素，您可以将其视为元素的附加"属性(寓言地
从技术上讲不是AttachedProperty).
请注意，如果类型具有由DictionaryKeyPropertyAttribute标记的属性，则您
实际上并不需要"x:Key"，而是可以使用该类型的"Key"属性(名称可能有所不同)，就像您建议的方式一样.
请注意，对于"x:Name"和"Name"，该关系与"x:Key"和"Key"的关系大致相同.
如果使用名称"，则该元素需要公开一个名为名称"的可写DP，
与键"相反的情况最常见-因为名称"是
的DP
每个FrameworkElement和FrameworkContentElement，因此XAML中使用了超过90％的元素，
所以这就是为什么Name和x:Name经常显示为同义词并且可以互换的原因
(它们并不完整)，但是"x:Key"和"Key"却没有.
If it was "Key" rather than "x:Key" this would require "Key" to be an "attribute" of
the "element" added as a resource, according to the syntax rules of XAML and even XML.
In WPF this would mean that every object added as a resource
would need to expose a writable DependencyProperty named "Key".
This would rule out all types that are not DependencyObjects - such as strings or URIs or
ViewModels instances - and more over all those that don''t have such DP named "Key",
so merely all objects commonly used as resources!
With the implementation as "x:Key" directive the key doesn''t need to be a true attribute of
the element added, you can look it as kind of an "attached" attribute to the element (just allegorically
not technically an AttachedProperty).
Note that if a type has a property marked by the DictionaryKeyPropertyAttribute then you
actually don''t need the "x:Key" but may rather use the "Key" property of that type (which may have a different name) - just the way you proposed.
Note that for "x:Name" and "Name" the relation is about the same as for "x:Key" and "Key".
If you use "Name" the element needs to expose a writable DP named "Name",
which in contrast to "Key" is most often the case - because "Name" is a DP of
every FrameworkElement and FrameworkContentElement, so >90% of elements used in XAML,
so that''s why Name and x:Name often appear as synonyms and mutually interchangeable
(which they are not fully) but "x:Key" and "Key" do not.
这同样适用于XAML中的所有x:属性
The same applies to all x: attributtes in XAML
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