路由事件和依赖项属性.NET包装器混乱 [英] Routed events and dependency properties .NET wrapper confusion

问题描述

我是WPF的新手，对包装路由事件和依赖项属性的语法感到困惑 我在许多来源中都看到，路由事件和依赖项属性是像这样包装的

I'm new to WPF and have a confusion about wrapping syntax of routed events and dependency properties I've seen on many sources that routed events and dependency properties are wrapped like this

// Routed Event
public event RoutedEventHandler Click
{
 add
 {
  base.AddHandler(ButtonBase.ClickEvent, value);
 }
 remove
 {
  base.RemoveHandler(ButtonBase.ClickEvent, value);
 }
}

// Dependency Property
public Thickness Margin
{
 set { SetValue(MarginProperty, value); }
 get { return (Thickness)GetValue(MarginProperty); }
}

我从未见过在C#中添加/删除/设置/获取某种关键字.这些是作为关键字的C#语言的一部分吗，并且因为我不是C ++程序员而没有在C#中工作，所以我从未经历过或与他们合作过?如果不是关键字，那么如果它们不是C#的一部分，那么编译器将如何处理它们以及它们如何工作

I have never seen add / remove / set / get sort of keywords in C#. Are these are part of C# language as Keywords and i never experienced or worked with them because i didn't worked in C# as pro i'm a C++ programmer? If not keywords then how they are handled by compiler if they are not part of C# and how they are working

推荐答案

我将尝试为您总结一下:

I'm gonna try to sum it up for you:

依赖性属性:

public int MyProperty
{
    get { return (int)GetValue(MyPropertyProperty); }
    set { SetValue(MyPropertyProperty, value); }
}

// Using a DependencyProperty as the backing store for MyProperty.  This enables animation, styling, binding, etc...
public static readonly DependencyProperty MyPropertyProperty =
    DependencyProperty.Register("MyProperty", typeof(int), typeof(MyClass), new UIPropertyMetadata(MyDefaultValue));

这是完整的语法，您不必记住它，只需在Visual Studio中使用"propdp"代码段即可.
"get"必须返回它所引用类型的值(在我的示例中为int).每当你打电话

That's the full syntax, you don't have to memorize it, just use the "propdp" snippet in Visual Studio.
The "get" must return a value of the type it refers to (in my example, int). Whenever you call

int MyVar = MyProperty;

评估"get"中的代码.
该集合具有类似的机制，只有您拥有另一个关键字:"value"，这将是您分配给MyVariable的值:

The code inside "get" is evaluated.
The set has a similar mechanism, only you have another keyword: "value" which will be the value you assign to MyVariable:

MyProperty = 1;

将调用MyProperty的集合"，值"将为"1".

Will call the "set" of MyProperty and "value" will be "1".

现在为RoutedEvents:

Now for the RoutedEvents:

在C#中(就像在C ++中一样，如果我错了，请纠正我)，您可以订阅事件

In C# (as in C++, correct me if i'm wrong), to subscribe to an event, you do

MyProperty.MyEvent += MyEventHandler;

这将称为"add"->您正在向堆栈中添加一个处理程序. 现在，由于不会自动对其进行垃圾收集，并且我们想避免内存泄漏，因此我们可以这样做:

That will call the "add" --> you're adding a handler to the stack. Now since it is not automatically garbage-collected, and we want to avoid memory leaks, we do:

MyProperty.MyEvent -= MyEventHandler;

这样，当我们不再需要我们的对象时，可以安全地对其进行处理. 那是在评估删除"表达式时.

So that our object can be safely disposed of when we don't need it anymore. That's when the "remove" expression is evaluated.

这种机制可以让您一次完成多个操作，在WPF中广泛使用的示例是:

Those mechanism allow you to do multiple things on a single "get", a widely used example in WPF would be:

private int m_MyProperty;
public int MyProperty
{
   get
   {
      return m_MyProperty;
   }
   set
   {
      if(m_MyProperty != value)
      {
         m_MyProperty = value;
         RaisePropertyChanged("MyProperty");
       }
    }
}

在实现INotifyPropertyChanged的ViewModel中，它将通知View中的绑定属性已更改并且需要再次检索(因此它们将称为"get")

Which, in a ViewModel that implements INotifyPropertyChanged, will notify the bindings in your View that the property has changed and need to be retrieved again (so they will call the "get")

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