private Color _BorderColor = Color.Black;

         [Browsable(true),Description("边框颜色"),Category("自定义分组")]

         public Color BorderColor

         {

             get { return _BorderColor; }

             set

             {

                 _BorderColor = value;

                 this.Invalidate();

             }

         }

 using System;

 using System.Collections.Generic;

 using System.ComponentModel;

 using System.Diagnostics;

 using System.Drawing;

 using System.Linq;

 using System.Text;

 using System.Windows.Forms;

 namespace ControlLibrary

 {

     public partial class GroupBoxEx : GroupBox

     {

         private Color _BorderColor = Color.Black;

         [Browsable(true),Description("边框颜色"),Category("自定义分组")]

         public Color BorderColor

         {

             get { return _BorderColor; }

             set

             {

                 _BorderColor = value;

                 this.Invalidate();

             }

         }

         public GroupBoxEx()

         {

             InitializeComponent();

         }

         public GroupBoxEx(IContainer container)

         {

             container.Add(this);

             InitializeComponent();

         }

         /// <summary>

         /// 重写Onpaint

         /// </summary>

         /// <param name="e"></param>

         protected override void OnPaint(PaintEventArgs e)

         {

             //base.OnPaint(e);

             var vSize = e.Graphics.MeasureString(this.Text,this.Font);

             e.Graphics.Clear(this.BackColor);

             e.Graphics.DrawString(this.Text, this.Font, new SolidBrush(this.ForeColor), , );

             Pen vPen = new Pen(this._BorderColor);

             e.Graphics.DrawLine(vPen, , vSize.Height / , , vSize.Height / );

             e.Graphics.DrawLine(vPen, vSize.Width + , vSize.Height / , this.Width - , vSize.Height / );

             e.Graphics.DrawLine(vPen, , vSize.Height / , , this.Height - );

             e.Graphics.DrawLine(vPen, , this.Height - , this.Width - , this.Height - );

             e.Graphics.DrawLine(vPen, this.Width - , vSize.Height / , this.Width - , this.Height - );

         }

     }

 }