C#生成随机验证码代码分享

        private static int Next(int min, int max)
        {
            int value = Next(max - min) + min;
            return value;
        }
        #endregion

        #region 公共方法
        /// <summary>
        /// 绘制验证码
        /// </summary>
        public void CreateImage()
        {
            int int_ImageWidth = this.text.Length * letterWidth;
            Bitmap image = new Bitmap(int_ImageWidth, letterHeight);
            Graphics g = Graphics.FromImage(image);
            g.Clear(Color.White);
            for (int i = 0; i < 2; i++)
            {
                int x1 = Next(image.Width - 1);
                int x2 = Next(image.Width - 1);
                int y1 = Next(image.Height - 1);
                int y2 = Next(image.Height - 1);
                g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
            }
            int _x = -12, _y = 0;
            for (int int_index = 0; int_index < this.text.Length; int_index++)
            {
                _x += Next(12, 16);
                _y = Next(-2, 2);
                string str_char = this.text.Substring(int_index, 1);
                str_char = Next(1) == 1 ? str_char.ToLower() : str_char.ToUpper();