using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing;

namespace WindowsFormsApplication1
{
    [ToolboxItem(true)] 
    public partial class TextBoxLine : TextBox
    {
        public TextBoxLine()
        {
            InitializeComponent();

            this.SetStyle(ControlStyles.DoubleBuffer, true);
            this.BorderStyle = BorderStyle.None;  
        }

        public TextBoxLine(IContainer container)
        {
            container.Add(this);

            InitializeComponent();

            this.SetStyle(ControlStyles.DoubleBuffer, true);
            this.BorderStyle = BorderStyle.None;  
        }

        private bool m_DrawLine = false;
        public bool DrawLine
        {
            get
            {
                return this.m_DrawLine;
            }
            set
            {
                this.m_DrawLine = value;
                this.Invalidate();
            }
        }
        private Color _linecolor = Color.Black;
        /// 

        /// 线条颜色
        /// 
        public Color LineColor
        {
            get
            {
                return this._linecolor;
            }
            set
            {
                this._linecolor = value;
                this.Invalidate();
            }
        }

        [System.Runtime.InteropServices.DllImport("user32.dll ")]
        static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);
        [System.Runtime.InteropServices.DllImport("user32.dll ")]
        static extern IntPtr GetWindowDC(IntPtr hWnd);

        protected override void WndProc(ref Message m)
        {
            base.WndProc(ref   m);
            if (m.Msg == 0xf || m.Msg == 0x133)
            {
                if (this.DrawLine)
                {
                    IntPtr hDC = GetWindowDC(m.HWnd);
                    if (hDC.ToInt32() == 0)
                    {
                        return;
                    }
                    Graphics g = Graphics.FromHdc(hDC);
                    Pen p = new Pen(this._linecolor, 1);
                    Point p1 = new Point(0, this.Height - 1);
                    Point p2 = new Point(this.Width, Height - 1);
                    g.DrawLine(p, p1, p2);
                    m.Result = IntPtr.Zero;
                    ReleaseDC(m.HWnd, hDC);
                }
            }
        }
    }
}

成都创新互联专注为客户提供全方位的互联网综合服务，包含不限于成都网站建设、网站建设、秀峰网络推广、小程序开发、秀峰网络营销、秀峰企业策划、秀峰品牌公关、搜索引擎seo、人物专访、企业宣传片、企业代运营等，从售前售中售后，我们都将竭诚为您服务，您的肯定，是我们最大的嘉奖；成都创新互联为所有大学生创业者提供秀峰建站搭建服务，24小时服务热线：028-86922220，官方网址：www.cdcxhl.com

原文地址：http://blog.csdn.net/geovi/article/details/7399406

网站标题：WinFormTextBox下面横线展示
当前地址：http://hbruida.cn/article/jidcgs.html