调用INotifyPropertyChanged的PropertyChanged事件的最佳方法是什么？

实现INotifyPropertyChanged接口时,每次在类中更新属性时,您都要负责调用PropertyChanged事件.

这通常会导致以下代码:

    public class MyClass: INotifyPropertyChanged

        private bool myfield;
        public bool MyField
        {
            get { return myfield; }
            set
            {
                if (myfield == value)
                    return;
                myfield = value;
                OnPropertyChanged(new PropertyChangedEventArgs("MyField"));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

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

这是每个属性12行.

如果一个人能够装饰这样的自动属性会简单得多:

[INotifyProperty]
public double MyField{ get; set; }

但不幸的是,这是不可能的(例如,请参阅msdn上的这篇文章)

如何减少每个属性所需的代码量？

实际上,每个属性只有3-4行; 其他行在所有"通知"属性上摊销:

class Person : INotifyPropertyChanged
{
    #region INotifyPropertyChanged: Shared bit
    public event PropertyChangedEventHandler PropertyChanged;

    private void OnPropertyChanged(PropertyChangedEventArgs e)
    {
        if (PropertyChanged != null)
            PropertyChanged(this, e);
    }
    #endregion

    private string _firstName;
    public string FirstName
    {
        get { return _firstName; }
        set
        {
            if (_firstName == value)
                return;
            _firstName = value;
            OnPropertyChanged(new PropertyChangedEventArgs("FirstName"));
        }
    }

    // Ditto for other properties
}

你可以尝试类似下面的东西,它分享更多的负载:

private string _firstName;
public string FirstName
{
    get { return _firstName; }
    set { SetNotifyingProperty("FirstName", ref _firstName, value); }
}
private void SetNotifyingProperty(string propertyName,
                                     ref T field, T value)
{
    if (value.Equals(field))
        return;
    field = value;
    OnPropertyChanged(new PropertyChangedEventArgs(propertyName));
}