WPF的Inkcanvas中添加图片选中的问题。

Question

我在InkCanvas想作为stroke添加图片，以便和墨迹一起处理。使用inkcanvas的select模式时。点击图片大部分区域不能选中，只有点击边框和从右上角到左下角一条斜线区域可以选中。谁能帮我了解下是哪里出了问题。

        private void picbtn1_Click(object sender, RoutedEventArgs e)
        {
            StylusPointCollection pts = new StylusPointCollection();
            pts.Add(new StylusPoint(100, 100)); // LeftTopPoint
            pts.Add(new StylusPoint(200, 100));
            pts.Add(new StylusPoint(100, 200));
            pts.Add(new StylusPoint(200, 200));
            Stroke s = new CustomStroke1(pts);
            ink.Strokes.Add(s);
        }

        #region 自定义画图片1
        public class CustomStroke1 : Stroke
        {
            private StylusPointCollection s;
            public CustomStroke1(StylusPointCollection stylusPoints) : base(stylusPoints)
            {
                this.s = stylusPoints;
            }

            //public bool IsSelected
            //{
            //    //get
            //    //{
            //    //    PropertyInfo property = typeof(Stroke).GetProperty("IsSelected",
            //    //       System.Reflection.BindingFlags.Instance |
            //    //       System.Reflection.BindingFlags.GetProperty |
            //    //       System.Reflection.BindingFlags.NonPublic);
            //    //    return (bool)property.GetValue(this, null);
            //    //}
            //}




            protected override void DrawCore(DrawingContext drawingContext, DrawingAttributes drawingAttributes)
            {
                ImageSource imageSource = new BitmapImage(new Uri("pack://application:,,,/0.bmp"));
                System.Windows.Point topLeft = new System.Windows.Point(StylusPoints[0].X, StylusPoints[0].Y);//100, 100
                System.Windows.Point topRight = new System.Windows.Point(StylusPoints[1].X, StylusPoints[1].Y);//200, 100
                System.Windows.Point centerLeft = new System.Windows.Point(StylusPoints[2].X, StylusPoints[2].Y);//100, 200
                System.Windows.Point centerRight = new System.Windows.Point(StylusPoints[3].X, StylusPoints[3].Y);//200, 200
                PathGeometry pathGeomery = new PathGeometry();
                PathSegmentCollection pathCollection = new PathSegmentCollection();
                pathCollection.Add(new LineSegment(topLeft, true));
                pathCollection.Add(new LineSegment(topRight, true));
                pathCollection.Add(new LineSegment(centerRight, true));
                pathCollection.Add(new LineSegment(centerLeft, true));
                pathCollection.Add(new LineSegment(topLeft, true));
                PathFigure pathFigure = new PathFigure();
                pathFigure.IsClosed = true;
                pathFigure.IsFilled = true;
                

                pathFigure.StartPoint = topLeft;
                
                pathFigure.Segments = pathCollection;
                //图片刷
                ImageBrush myimageBrush = new ImageBrush();
                myimageBrush.ImageSource = imageSource;
                PathFigureCollection pathFigureCollection = new PathFigureCollection();
                pathFigureCollection.Add(pathFigure);
                pathGeomery.Figures = pathFigureCollection;
                drawingContext.DrawGeometry(myimageBrush, new System.Windows.Media.Pen(System.Windows.Media.Brushes.Blue, 2), pathGeomery);
                this.s = null;

            }
        }

        #endregion

Answer 1

你好 子夜十分：

问题出在你对Stroke的继承。

你在DrawCore中的代码只是描述了如何绘制出此Stroke的外观，对于Stroke内部，其逻辑形状依然是你设置的四个点：

(100, 100)，
(200, 100)，
(100, 200)，
(200, 200)。

于是，该Stroke的形状为“Z”字形，如图：

于是，只有当点击红线所示“Z”字形墨迹时，整个Stroke才会被选中（你可以试试，左右边框是选中不了的）。