PropertyChanged为空

Question

首先，我也认为这是一个小问题，但我真的不知道如何解决它！

我写了一个"Point“类来实现PropertyChanged，但是它不能工作，因为"PropertyChanged==null”是真的。

这里是mySource：

public class RaPoint : DependencyObject, INotifyPropertyChanged
{
    public RaPoint() : this(0,0)
    {
    }

    public RaPoint(double X, double Y)
    {
        this.X = X;
        this.Y = Y;
    }

    public RaPoint(Point Position)
        : this(Position.X, Position.Y)
    {
    }

    public RaPoint(RaPoint Position)
        : this(Position.X, Position.Y)
    {
    }

    public static RaPoint operator +(RaPoint P1, Vector V1)
    {
        P1.X += V1.X;
        P1.Y += V1.Y;
        return P1;
    }

    public double X
    {
        get
        {
            return (double)GetValue(XProperty);
        }
        set
        {
            SetValue(XProperty, value);
            RaisePropertyChanged("X");
        }
    }
    public static readonly DependencyProperty XProperty = DependencyProperty.Register("X", typeof(double), typeof(RaPoint), new FrameworkPropertyMetadata()
    {
        BindsTwoWayByDefault = true,
        DefaultUpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged
    }
    );


    public double Y
    {
        get
        {
            return (double)GetValue(YProperty);
        }
        set
        {
            SetValue(YProperty, value);
            RaisePropertyChanged("Y");
        }
    }
    public static readonly DependencyProperty YProperty = DependencyProperty.Register("Y", typeof(double), typeof(RaPoint), new FrameworkPropertyMetadata()
    {
        BindsTwoWayByDefault = true,
        DefaultUpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged
    }
    );


    public override string ToString()
    {
        return String.Format("X:{0} Y:{1}", X.ToString(), Y.ToString());
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void RaisePropertyChanged(string name)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(name));
        }
    }

    public void Set(double X, double Y)
    {
        this.X = X;
        this.Y = Y;
    }

    public void Set(RaPoint Position)
    {
        Set(Position.X, Position.Y);
    }

    public void Set(Point Position)
    {
        Set(Position.X, Position.Y);
    }
}

谢谢!

Answer 1

您是否在对象DataContext上设置了正确的值？例如: this.DataContext = raPoint；