如何重写panel边框

Question

panel边框设置成SingleLine后只有一种颜色黑色，我想换成别的颜色，但又不想用第三方控件，请教如何实现？

Answer 1

设置this.panel1.BorderStyle = BorderStyle.None;private void panel1_Paint(object sender, PaintEventArgs e)
        {
            e.Graphics.DrawRectangle(new Pen(Brushes.Red), new Rectangle(0, 0, this.panel1.Width - 1, this.panel1.Height - 1));
        }

Answer 2

这样有个问题，当panel有滚动条，滑动滚动条时，就会重绘在错误的位置，多出很多条竖线来

Answer 3

public class MyPanel : Panel
    {
        Color _BorderColor = Color.Blue;        public Color BorderColor
        {
            get
            {
                return _BorderColor;
            }
            set
            {
                _BorderColor = value;
            }
        }        [DllImport("user32.dll")]
        static extern IntPtr GetWindowDC(IntPtr hWnd);
        [DllImport("user32.dll")]
        public static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);        protected override void WndProc(ref Message m)
        {
            if (m.Msg == 0x85)
            {
                IntPtr hdc = GetWindowDC(Handle);
                Graphics g = Graphics.FromHdc(hdc);
                Pen pen = new Pen(_BorderColor, 2);
                try
                {
                    Rectangle rect = Bounds;
                    rect.Offset(-rect.Location.X, -rect.Location.Y);
                    g.DrawRectangle(pen, rect);
                }
                finally
                {
                    g.Dispose();
                    ReleaseDC(Handle, hdc);
                }
            }
            else
                base.WndProc(ref m);
        }
    }