绘图报错，读取或写入受保护的内存，该如何解决？

报错如下图所示


贴出代码如下：
     public void paint(Graphics g)
        {

           GraphicsPath path = new GraphicsPath();

            Rectangle rectangle = new Rectangle(pt, new Size(recWidth, recHeight));
            Rectangle toggleNode = Rectangle.Empty; //the [+] [-]
            switch (this.shapeType)
            {
                case ShapeTypes.Rectangle:
                    path = new GraphicsPath();                    
                    path.AddRectangle(rectangle);
                    break;
                case ShapeTypes.SM:
                    path = new GraphicsPath();
                    path.AddEllipse(rectangle);
                    break;
                case ShapeTypes.Ellipse:
                    path = new GraphicsPath();
                    path.AddEllipse(rectangle);
                    break;               
            }

            Region region = new Region(path);



            g.FillRegion(new SolidBrush(fillColor), region);



            if (frameWidth == 0)
                g.FillRectangle(Brushes.White, new Rectangle(pt.X, pt.Y, recWidth + 2, recHeight + 2));
            else
                g.FillRectangle(Brushes.White, new Rectangle(pt.X, pt.Y, recWidth + frameWidth, recHeight + frameWidth));
        ama:
            try
            {                

                g.FillPath(new SolidBrush(fillColor), path);
            
                if (frameWidth != 0)
                {
                    if (!isRuanSheng)
                    {
                        Pen mypen = new Pen(frameColor, frameWidth);
                        g.DrawPath(mypen, path);
                    }
                    else
                    {
                        Pen mypen = new Pen(Color.FromArgb(frameColor.A/2,frameColor.G/2,frameColor.B/2), frameWidth+1);
                        g.DrawPath(mypen, path);
                    }
                }
            }
            catch (AccessViolationException ex)
            {
                goto ama;
            }
            if (isHovered)
            {
                g.DrawPath(new Pen(Color.Blue,frameWidth), path);
                g.DrawRectangle(new Pen(Color.Blue, frameWidth), ReSizeRec);
            }
            if (isSelected)
            {
                g.DrawPath(new Pen(Color.Green, frameWidth), path);
                g.DrawRectangle(new Pen(Color.Green, frameWidth), ReSizeRec);
                g.DrawRectangle(new Pen(Color.Green, frameWidth), ConRec);
            }
            if (relatedImage == null)
            {

                StringFormat sf = new StringFormat();
                sf.Alignment = StringAlignment.Center;
                sf.LineAlignment = StringAlignment.Center;
                Brush brush = new SolidBrush(this.fontColor);
                g.DrawString(text, font, brush, rectangle, sf);
            }
            else
            {
                StringFormat sf = new StringFormat();
                sf.Alignment = StringAlignment.Center;
                sf.LineAlignment = StringAlignment.Center;
                Brush brush = new SolidBrush(this.fontColor);

                //Rectangle rec1 = new Rectangle();
                //rec1.Location = rectangle.Location;
                //rec1.Width = rectangle.Width * 3 / 4;
                //rec1.Height = rectangle.Height;

                Rectangle rec2 = new Rectangle();
                rec2.Location = new Point(pt.X+ rectangle.Width * 3 / 4 + 1, pt.Y+rectangle.Height/4);
                rec2.Width = rectangle.Width / 4 - 1;
                rec2.Height = rectangle.Height/2;

                Rectangle rec1 = new Rectangle();
                //rec1.Location = rectangle.Location;
                rec1.Location = new Point(pt.X+recWidth/4,pt.Y+recHeight/4);
                rec1.Width = recWidth / 2;
                rec1.Height = recHeight / 2;

                //g.DrawString(text, font, brush, rectangle, sf);
                g.DrawString(text, font, brush, rec2, sf);
                //g.DrawImage(relatedImage, rec1);
                g.DrawImage(relatedImage, rec1);

            }
        }

求高手帮忙 c#; graphics fillpath

补充：.NET技术 ,  C#