验证码控件的改进

对生成的验证码图片进行了随机处理，加大了破解难度。


但还没解决设计时支持的问题。不知为何？

代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
using System.Drawing.Imaging;

namespace Common.Web.AppControl
{
    /**//// <summary>
    /// 效验码控件
    /// </summary>
    /// <summary>
    /// 上传进度条控件
    /// </summary>
    /// <example>
    /// Web.config 配置
    /// <?xml version="1.0"?>
    ///<configuration>
    ///    <configSections>
    ///        <sectionGroup name="dataGroup">
    ///             <!--加密算法-->
    ///             <section name="encrypt" type="Common.Framework.ProviderConfigurationHandler, Common"/>
    ///        </sectionGroup>
    ///    </configSections>
    ///    <dataGroup>
    ///            <encrypt defaultProvider="EncryptRe">
    ///                <providers>
    ///                  <clear/>
    ///                  <!--可逆-->
    ///                     <add name="EncryptRe" type="Common.DEncrypt.EncryptProvider, Common" classname="Common.DEncrypt.EncryptRe, Common"/>
    ///                     <!--不可逆-->
    ///                     <add name="EncryptUnRe" type="Common.DEncrypt.EncryptProvider, Common" classname="Common.DEncrypt.EncryptUnRe, Common"/>
    ///                </providers>
    ///            </encrypt>
    ///   </dataGroup>
    ///   <system.web>
    ///         <httpHandlers>
    ///           <add verb="*" path="CommonToolsASHX.ashx" type="Common.Web.AppControl.CommonToolsASHX, Common" />
    ///         </httpHandlers>
    ///   </system.web>
    ///</configuration>
    /// </example>
    [Designer(typeof(WebCheckCode.Designer))]
    [ToolboxData("<{0}:WebCheckCode runat=server></{0}:WebCheckCode>")]   
    public class WebCheckCode : Control, INamingContainer
    {
        WebCheckCode#region WebCheckCode
        private#region private
        private string checkwordNow
        {
            get
            {
                return "CheckWordNow" + this.UniqueID;
            }
        }
        private string checkwordLength
        {
            get
            {
                return "CheckWordLength" + this.UniqueID;
            }
        }
        private string checkwordType
        {
            get
            {
                return "CheckWordType" + this.UniqueID;
            }
        }

        private string imgBuildFileUrl
        {
            get
            {
                return "ImgBuildFileUrl" + this.UniqueID;
            }
        }
        private string imgCss
        {
            get
            {
                return "imgCss" + this.UniqueID;
            }
        }
        private string GetRandomWord()
        {
            Common.StrHelp.Random random = new Common.StrHelp.Random(this.Length);
            return random.GetRandomWord(this.WordType);
        }

        private string _CheckWordNew = null;
        private string CheckWordNew
        {
            get
            {
                if (this._CheckWordNew == null)
                {
                    this._CheckWordNew = Common.DEncrypt.Factory.GetInstanceRe().EncryptString(this.GetRandomWord());
                }
                return this._CheckWordNew;
            }
        }
        private string _CheckWordNow;
        protected string _ImgBuildFileUrl = Common.Web.UrlInfo.Url_CommonToolsASHX;
        private string _ImgCss = null;
        private Common.StrHelp.RandomWordType _WordType = Common.StrHelp.RandomWordType.Num;
        private int _CheckWorkLength = 4;
        #endregion

        属性#region 属性

        Value　效验码值#region Value　效验码值
        /**//// <summary>
        /// 效验码值
        /// </summary>
        [Bindable(true)]
        [Category("Appearance")]
        [Localizable(true)]
        public string Value
        {
            get
            {
                return Common.DEncrypt.Factory.GetInstanceRe().DecryptString(this._CheckWordNow);
            }
        }
        #endregion

        WordType　控件字符串类型#region WordType　控件字符串类型
        /**//// <summary>
        /// 控件字符串类型　WordType
        /// </summary>
        [Bindable(true)]
        [Category("Appearance")]
        [Localizable(true)]
        public Common.StrHelp.RandomWordType WordType
        {
            get
            {
                return this._WordType;
            }
            set
            {
                this._WordType = value;
            }
        }
        #endregion

        Length 效验码长度#region Length 效验码长度
        /**//// <summary>
        /// 效验码长度
        /// </summary>
        [Bindable(true)]
        [Category("Appearance")]
        [DefaultValue("4")]
        [Localizable(true)]
        public int Length
        {
            get
            {
                return this._CheckWorkLength;
            }
            set
            {
                this._CheckWorkLength = value;
            }
        }
        #endregion

        ImgBuildFileUrl 输出图片的地址#region ImgBuildFileUrl 输出图片的地址
        /**//// <summary>
        /// 输出图片的地址
        /// </summary>
        [Bindable(true)]
        [Category("Appearance")]
        [Localizable(true)]
        [UrlProperty]
        public virtual string ImgBuildFileUrl
        {
            get
            {
                return this._ImgBuildFileUrl;
            }
            set
            {
                this._ImgBuildFileUrl = value;
            }
        }
        #endregion

        ImgCss 图片样式#region ImgCss 图片样式
        /**//// <summary>
        /// 图片样式
        /// </summary>
        [Bindable(true)]
        [Category("Appearance")]
        [Localizable(true)]
        public string ImgCss
        {
            get
            {
                return this._ImgCss;
            }
            set
            {
                this._ImgCss = value;
            }
        }
        #endregion

        #endregion

        override#region override
        protected override object SaveViewState()
        {
            System.Collections.Specialized.ListDictionary ld = new System.Collections.Specialized.ListDictionary();
            ld.Add(checkwordType, this._WordType);
            ld.Add(checkwordLength, this._CheckWorkLength);
            ld.Add(checkwordNow, this.CheckWordNew);
            ld.Add(imgBuildFileUrl, this._ImgBuildFileUrl);
            ld.Add(imgCss, this._ImgCss);
            return ld;
        }

        protected override void LoadViewState(object savedState)
        {
            if (savedState != null)
            {
                System.Collections.Specialized.ListDictionary ld = (System.Collections.Specialized.ListDictionary)savedState;
                this._WordType = (Common.StrHelp.RandomWordType)ld[checkwordType];
                this._CheckWorkLength = (int)ld[checkwordLength];
                this._CheckWordNow = (string)ld[checkwordNow];
                this._ImgBuildFileUrl = (string)ld[imgBuildFileUrl];
                this._ImgCss = (string)ld[imgCss];
            }
        }

        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);
        }

        protected override void Render(HtmlTextWriter writer)
        {
            string url = string.Format(@"{0}?{1}={2}&{3}={4}", this.ImgBuildFileUrl, Common.Web.UrlInfo.Key_Ctrl_Identity, Common.Web.UrlInfo.Value_WebCheckCode_Identity, Common.Web.UrlInfo.Key_WebCheckCode_Param, this.CheckWordNew);
            writer.AddAttribute("src", url);
            if (this._ImgCss != null && this._ImgCss != "")
            {
                writer.AddAttribute("class", this._ImgCss);
            }
            writer.RenderBeginTag(HtmlTextWriterTag.Img);
            writer.RenderEndTag();
            base.Render(writer);
        }
        #endregion
        #endregion

        Designer#region Designer
        /**//// <summary>
        /// <see cref="WebCheckCode"/> 服务器控件设计器。
        /// </summary>
        public class Designer : System.Web.UI.Design.ControlDesigner
        {
            /**//// <summary>
            /// 获取用于在设计时表示关联控件的 HTML。
            /// </summary>
            /// <returns>用于在设计时表示控件的 HTML。</returns>
            public override string GetDesignTimeHtml()
            {
                return "<span style='border-right: #ff6666 1px dotted; border-top: #ff6666 1px dotted; border-left: #ff6666 1px dotted; width: 20px; border-bottom: #ff6666 1px dotted; height: 70px; background-color: #ffcc66;font-size:13px; padding-right: 3px; padding-left: 3px; padding-bottom: 3px; padding-top: 3px;'>验证码</span>";
            }
        }
        #endregion

        WebCheckCode ashx#region WebCheckCode ashx
        internal class Ashx_WebCheckCode : ICtrl_Ashx
        {
            /**//// <summary>
            /// 随机数产生器
            /// </summary>
            private Random random = new Random();

            ICtrl_Ashx Members#region ICtrl_Ashx Members

            public void WriteContent(HttpResponse response, HttpRequest request)
            {
                response.Cache.SetCacheability(HttpCacheability.Public);
                response.BufferOutput = false;
                //写入图片
                this.WriteSingleImage(this.ImgStr, response);
            }

            /**//// <summary>
            /// 输出类型
            /// </summary>
            public string ContentType
            {
                get
                {
                    return "image/gif";
                }
            }

            #endregion
            /**//// <summary>
            /// 写入文字
            /// </summary>
            protected virtual string ImgStr
            {
                get
                {
                    return Common.Web.UrlInfo.Value_WebCheckCode_Param;
                }
            }

           
            /**//// <summary>
            /// 图片类型
            /// </summary>
            protected virtual ImageFormat WriteImageFormat
            {
                get
                {
                    return ImageFormat.Gif;
                }
            }

            /**//// <summary>
            /// 字体（GraphicsUnit 必须为像素Pixel）
            /// </summary>
            protected virtual Font WriteFont
            {
                get
                {
                    string fontfamily = this.GetFontfamily();
                    FontStyle fontStyle = this.GetFontStyle();
                    float fontSize = this.GetFontSize();
                   
                    return new System.Drawing.Font(fontfamily, fontSize, fontStyle, GraphicsUnit.Pixel);
                }
            }

            /**//// <summary>
            /// 得到随机字体大小
            /// </summary>
            /// <param name="r">随机类</param>
            /// <returns>字体大小</returns>
            protected float GetFontSize()
            {
                int i = this.random.Next(4);
                if (i == 1)
                {
                    return (float)16.3;
                }
                else if (i == 2)
                {
                    return (float)16.4;
                }
                else if (i == 3)
                {
                    return (float)16.5;
                }
                else
                {
                    return (float)16.6;
                }
            }

            /**//// <summary>
            /// 得到随机字体样式
            /// </summary>
            /// <param name="r">随机类</param>
            /// <returns>字体样式</returns>
            protected FontStyle GetFontStyle()
            {
                int i = this.random.Next(4);
                if (i == 1)
                {
                    return FontStyle.Bold;
                }
                else if (i == 2)
                {
                    return FontStyle.Underline;
                }
                else if (i == 3)
                {
                    return FontStyle.Italic;
                }
                else
                {
                    return FontStyle.Regular;
                }
            }

            /**//// <summary>
            /// 得到随机字体
            /// </summary>
            /// <returns>字体名</returns>
            protected string GetFontfamily()
            {
                int i = this.random.Next(4);
                if (i == 1)
                {
                    return "Arial";
                }
                else if (i == 2)
                {
                    return "Perpetua";
                }
                else if (i == 3)
                {
                    return "Sylfaen";
                }
                else
                {
                    return "Tw Cen MT";
                }
            }

            /**//// <summary>
            /// 文字颜色
            /// </summary>
            protected virtual Color WriteColor
            {
                get
                {
                    int i = this.random.Next(4);
                    if (i == 1)
                    {
                        return Color.Red;
                    }
                    else if(i == 2)
                    {
                        return Color.Blue;
                    }
                    else if (i == 3)
                    {
                        return Color.SeaGreen;
                    }
                    else
                    {
                        return Color.Green;
                    }

                }
            }

            /**//// <summary>
            /// 文字宽度Pixel
            /// </summary>
            /// <param name="text">文字</param>
            /// <param name="font">字体</param>
            /// <returns>文字宽度Pixel</returns>
            protected virtual int GetImgWidth(string text, Font font)
            {
                int i = Common.Img.TextUse.GetTextWidth(text, font, System.Text.ASCIIEncoding.ASCII);
                if (text.Length == 1)
                    return i;
                else if (text.Length > 1 && text.Length < 7)
                {
                    return (int)(i * 4 / 5);
                }
                else
                {
                    return (int)(i * 5 / 7);
                }
            }

            /**//// <summary>
            /// 文字高度Pixel
            /// </summary>
            /// <param name="font">字体</param>
            /// <returns>文字高度Pixel</returns>
            protected virtual int GetImgHeight(Font font)
            {
                return Common.Img.TextUse.GetTextHeight(font) + 4;
            }

            /**//// <summary>
            /// 得到绘图
            /// </summary>
            /// <param name="b">Bitmap</param>
            /// <returns></returns>
            protected virtual Graphics GetImgGraphics(Bitmap b)
            {
                return Graphics.FromImage(b);
            }

            /**//// <summary>
            /// 画背景
            /// </summary>
            /// <param name="g"></param>
            /// <param name="width"></param>
            /// <param name="height"></param>
            protected virtual void DrawBackground(Graphics g, int width, int height)
            {
                Common.Img.DrawPic.DrawRoundRectangle(new SolidBrush(BackgroundColor), 0, 0, width, height, 0, g);
            }

            /**//// <summary>
            /// 背景颜色
            /// </summary>
            protected virtual Color BackgroundColor
            {
                get
                {
                    return Color.Wheat;
                }
            }

            /**//// <summary>
            /// 写入图片
            /// </summary>
            /// <param name="imgStr"></param>
            protected virtual void WriteSingleImage(string imgStr, HttpResponse response)
            {
                int width = this.GetImgWidth(imgStr, this.WriteFont) + 4;
                int height = this.GetImgHeight(this.WriteFont) + 1;
                Bitmap b = new Bitmap(width, height);

                Graphics g = this.GetImgGraphics(b);
                this.DrawBackground(g, width, height);
               
                this.WriteNoise(g, b);

                Random r = new Random();
                float oneWidth = width / imgStr.Length;
                float x = (float)((r.Next(10) + 0.1) / 10);
               
                for (int i = 0; i < imgStr.Length; i++)
                {
                    SolidBrush brush = new SolidBrush(this.WriteColor);
                    float y = (float)((r.Next(10) + 0.1)) / 10;
                    g.DrawString(imgStr[i].ToString(), this.WriteFont, brush, x, y);
                    x += oneWidth;
                }

                System.IO.MemoryStream m = new System.IO.MemoryStream();
                b.Save(m, this.WriteImageFormat);
                byte[] bt = m.GetBuffer();
                response.OutputStream.Write(bt, 0, bt.Length);
            }

            /**//// <summary>
            /// 给图片加干扰
            /// </summary>
            /// <param name="graphics">Graphics</param>
            /// <param name="bitmap">Bitmap</param>
            protected virtual void WriteNoise(Graphics graphics, Bitmap bitmap)
            {
                Random random = new Random();
                //画图片的背景噪音线
                for (int i = 0; i < 25; i++)
                {
                    int x1 = random.Next(bitmap.Width);
                    int x2 = random.Next(bitmap.Width);
                    int y1 = random.Next(bitmap.Height);
                    int y2 = random.Next(bitmap.Height);

                    graphics.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
                }

                //画图片的前景噪音点
                for (int i = 0; i < 100; i++)
                {
                    int xx = random.Next(bitmap.Width);
                    int yy = random.Next(bitmap.Height);
                    bitmap.SetPixel(xx, yy, Color.FromArgb(random.Next()));
                }

                graphics.DrawRectangle(new Pen(Color.Silver), 0, 0, bitmap.Width - 1, bitmap.Height - 1);
            }
            
        }
        #endregion
    }

}