.net 如何创建只读依赖属性？
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How do You Create a Read-Only Dependency Property?
提问by Giffyguy
How do you create a read-only dependancy property? What are the best-practices for doing so?
如何创建只读依赖属性？这样做的最佳做法是什么？
Specifically, what's stumping me the most is the fact that there's no implementation of
具体来说，最让我难受的是没有实施
DependencyObject.GetValue()
that takes a System.Windows.DependencyPropertyKeyas a parameter.
将 aSystem.Windows.DependencyPropertyKey作为参数。
System.Windows.DependencyProperty.RegisterReadOnlyreturns a DependencyPropertyKeyobject rather than a DependencyProperty. So how are you supposed to access your read-only dependency property if you can't make any calls to GetValue? Or are you supposed to somehow convert the DependencyPropertyKeyinto a plain old DependencyPropertyobject?
System.Windows.DependencyProperty.RegisterReadOnly返回一个 DependencyPropertyKey对象而不是 a DependencyProperty。那么，如果您无法调用 GetValue，您应该如何访问您的只读依赖项属性？或者你应该以某种方式将它转换DependencyPropertyKey成一个普通的旧DependencyProperty对象？
Advice and/or code would be GREATLY appreciated!
建议和/或代码将不胜感激！
回答by Kenan E. K.
It's easy, actually (via RegisterReadOnly):
实际上很简单（通过RegisterReadOnly）：
public class OwnerClass : DependencyObject // or DependencyObject inheritor
{
private static readonly DependencyPropertyKey ReadOnlyPropPropertyKey
= DependencyProperty.RegisterReadOnly(
nameof(ReadOnlyProp),
typeof(int), typeof(OwnerClass),
new FrameworkPropertyMetadata(default(int),
FrameworkPropertyMetadataOptions.None));
public static readonly DependencyProperty ReadOnlyPropProperty
= ReadOnlyPropPropertyKey.DependencyProperty;
public int ReadOnlyProp
{
get { return (int)GetValue(ReadOnlyPropProperty); }
protected set { SetValue(ReadOnlyPropPropertyKey, value); }
}
//your other code here ...
}
You use the key only when you set the value in private/protected/internal code. Due to the protected ReadOnlyPropsetter, this is transparent to you.
仅当您在私有/受保护/内部代码中设置值时才使用该密钥。由于受保护的ReadOnlyPropsetter，这对您来说是透明的。
