圆角面板

1 效果如

 

 

2 代码编写

    public partial class UPanel : Panel
    {
        public UPanel()
        {
            InitializeComponent();
        }

        private Color bgColor = Color.Gray;

        /// <summary>
        /// 背景色（渐变色中，颜色1）
        /// </summary>
        [DefaultValue(typeof(Color), "Gray"), Description("控件背景色")]
        public Color BgColor
        {
            get { return bgColor; }
            set
            {
                bgColor = value;
                Refresh();
            }
        }

        private Color borderColor = Color.Red;
        [DefaultValue(typeof(Color), "Gray"), Description("控件边框颜色")]
        public Color BorderColor
        {
            get { return borderColor; }
            set
            {
                borderColor = value;
                Refresh();
            }
        }

        private int borderWidth = 0;
        [DefaultValue(typeof(int), "0"), Description("控件边框粗细")]
        public int BorderWidth
        {
            get { return borderWidth; }
            set
            {
                borderWidth = value;
                Refresh();
            }
        }

        [DefaultValue(typeof(Color), "Gray"), Description("控件背景颜色2")]
        private Color bgColor2 = Color.White;
        public Color BgColor2
        {
            get { return bgColor2; }
            set
            {
                bgColor2 = value;
                Refresh();
            }
        }


        [DefaultValue(typeof(int), "5"), Description("圆角弧度大小")]
        private int radius = 5;
        public int Radius
        {
            get { return radius; }
            set
            {
                radius = value;
                Refresh();
            }
        }

        [DefaultValue(typeof(LinearGradientMode), "Vertical"), Description("渐变方式")]
        private LinearGradientMode gradientMode = LinearGradientMode.Vertical;
        public LinearGradientMode GradientMode
        {
            get { return gradientMode; }
            set
            {
                gradientMode = value;
                Invalidate();
            }
        }
        Rectangle r;
        protected override void OnSizeChanged(EventArgs e)
        {
            base.OnSizeChanged(e);
            r = new Rectangle(0, 0, this.Width, this.Height);
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            Graphics g = e.Graphics;
            g.SmoothingMode = SmoothingMode.HighQuality;
            r.Width = this.Width;
            r.Height = this.Height;
            r.Width -= 1;
            r.Height -= 1;
            GraphicsPath path = new GraphicsPath();
            GraphicsPath path2 = new GraphicsPath();
            Rectangle rect;
            if (this.BorderWidth > 0)
            {
                path = PaintClass.GetRoundRectangle(r, radius);
                using (Pen pen = new Pen(this.BorderColor, BorderWidth))
                {
                    g.DrawPath(pen, path);
                }
                rect = new Rectangle(r.X + BorderWidth, r.Y + BorderWidth, r.Width - 2 * BorderWidth, r.Height - 2 * BorderWidth);
                path2 = PaintClass.GetRoundRectangle(rect, radius-1);
            }
            else
            {
                path2 = PaintClass.GetRoundRectangle(r, radius);
                rect = r;
            }
            if (this.BgColor2 != Color.Transparent)
            {
                //线型渐变画刷
                LinearGradientBrush bgBrush = new LinearGradientBrush(rect, BgColor, BgColor2, GradientMode);
                g.FillPath(bgBrush, path2);//填充圆角矩形内部
            }
            else
            {
                Brush b = new SolidBrush(BgColor);
                g.FillPath(b, path2);//填充圆角矩形内部
            }
          
        
        }

    }