向 XAML 中的元素添加自定义属性? [英] Adding custom attributes to an element in XAML?

问题描述

在 html 中，没有什么可以阻止您创建自定义属性，因为它实际上是 xml，例如

In html, there is nothing preventing you from creating custom attributes, since it is effectively xml such as

<span myProperty="myValue"></span>

然后您可以通过 javascript 读取该属性.

Then you can read that property via javascript.

你能在 wpf 中做同样的事情吗?例如:

Can you do the same thing in wpf? For example:

<Canvas MyProperty="MyValue" Name="MyCanvas" DataContext="{Binding}" Background="Black" Margin="181,0,0,0"></Canvas>

如果是这样，您将如何访问该属性?例如:

and If so how would you access that property? For example:

MyCanvas.MyProperty;

推荐答案

最接近的是 附加属性.基本上，另一个类定义了一个已知属性(即 MyProperty)，该属性可以设置在其他元素上.

The closest you can get are attached properties. Basically, another class defines a known property (i.e. MyProperty), which can be set on other elements.

一个例子是 Canvas.Left 属性，Canvas 使用它来定位子元素.但是任何类都可以定义附加属性.

An example would be the Canvas.Left property, which is used by the Canvas to position a child element. But any class can define an attached property.

附加属性是附加行为背后的关键，这是一个很棒的功能WPF/Silverlight.

Attached properties are the key behind attached behaviors, which is a great feature of WPF/Silverlight.

这是一个示例类:

namespace MyNamespace {
    public static class MyClass {

        public static readonly DependencyProperty MyPropertyProperty = DependencyProperty.RegisterAttached("MyProperty",
            typeof(string), typeof(MyClass), new FrameworkPropertyMetadata(null));

        public static string GetMyProperty(UIElement element) {
            if (element == null)
                throw new ArgumentNullException("element");
            return (string)element.GetValue(MyPropertyProperty);
        }
        public static void SetMyProperty(UIElement element, string value) {
            if (element == null)
                throw new ArgumentNullException("element");
            element.SetValue(MyPropertyProperty, value);
        }
    }
}

然后在 XAML 中你可以像这样使用它:

Then in XAML you can use it like so:

xmlns:local="clr-namespace:MyNamespace"

<Canvas local:MyClass.MyProperty="MyValue" ... />

您可以使用 MyClass.GetMyProperty 从代码中获取属性，并传入设置属性的元素.

You can get the property from code using MyClass.GetMyProperty and passing in the element on which the property is set.

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