在 C 6 中實現 INotifyPropertyChanged

INotifyPropertyChange 的實現可能容易出錯，因為介面需要將屬性名稱指定為字串。為了使實現更加健壯，可以使用屬性 CallerMemberName。

class C : INotifyPropertyChanged
{
    // backing field
    int offset;
    // property
    public int Offset
    {
        get
        {
            return offset;
        }
        set
        {
            if (offset == value)
                return;
            offset = value;
            RaisePropertyChanged();
        }
    }

    // helper method for raising PropertyChanged event
    void RaisePropertyChanged([CallerMemberName] string propertyName = null) =>
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));

    // interface implemetation
    public event PropertyChangedEventHandler PropertyChanged;
}

如果你有幾個實現 INotifyPropertyChanged 的類，你可能會發現將介面實現和輔助方法重構為公共基類很有用：

class NotifyPropertyChangedImpl : INotifyPropertyChanged
{
    protected void RaisePropertyChanged([CallerMemberName] string propertyName = null) =>
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));

    // interface implemetation
    public event PropertyChangedEventHandler PropertyChanged;
}

class C : NotifyPropertyChangedImpl
{
    int offset;
    public int Offset
    {
        get { return offset; }
        set { if (offset != value) { offset = value; RaisePropertyChanged(); } }
    }
}