引发事件，每当一个属性值改变？

问题描述：

有一种属性，它的命名 ImageFullPath1

There is a property, it's named ImageFullPath1

public string ImageFullPath1 {get; set; }

我要火，只要它的价值变化的事件。我知道我可以提防与 INotifyPropertyChanged的改变，但我想这样做与事件。
我不知道我应该怎么做。
能否请你指导我？

I'm gonna fire an event whenever its value changed. I know I can beware of changing with INotifyPropertyChanged, but I wanna do it with events.
I don't know how I should do it.
Could you please guide me?

感谢。

答

在 INotifyPropertyChanged的接口是与事件实现。该接口有一个成员，的PropertyChanged ，它是一个事件，消费者可以订阅

The INotifyPropertyChanged interface is implemented with events. The interface has just one member, PropertyChanged, which is an event that consumers can subscribe to.

这是理查德发布的版本是不是安全。下面是如何安全地实现这个接口：

The version that Richard posted is not safe. Here is how to safely implement this interface:

public class MyClass : INotifyPropertyChanged
{
    private string imageFullPath;

    protected void OnPropertyChanged(PropertyChangedEventArgs e)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null)
            handler(this, e);
    }

    protected void OnPropertyChanged(string propertyName)
    {
        OnPropertyChanged(new PropertyChangedEventArgs(propertyName));
    }

    public string ImageFullPath
    {
        get { return imageFullPath; }
        set
        {
            if (value != imageFullPath)
            {
                imageFullPath = value;
                OnPropertyChanged("ImageFullPath");
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
}

请注意，这样做以下几件事：

Note that this does the following things:

抽象化属性更改通知方式，因此您可以轻松地应用这等性能;

Abstracts the property-change notification methods so you can easily apply this to other properties;

在使的PropertyChanged 委托的副本试图调用它（如果不这样做会创建一个竞争条件）。

Makes a copy of the PropertyChanged delegate before attempting to invoke it (failing to do this will create a race condition).

正确实施 INotifyPropertyChanged的接口。

如果你想的此外的创建通知了的的具体的性质被改变，你可以添加以下code：

If you want to additionally create a notification for a specific property being changed, you can add the following code:

protected void OnImageFullPathChanged(EventArgs e)
{
    EventHandler handler = ImageFullPathChanged;
    if (handler != null)
        handler(this, e);
}

public event EventHandler ImageFullPathChanged;

然后添加一行 OnImageFullPathChanged（EventArgs.Empty）行之后 OnPropertyChanged（ImageFullPath）。

引发事件，每当一个属性值改变？

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