MVC+EasyUI+三层新闻网站建立（三 验证码生成）

我们在项目中的NewWeb.Common类库里面建立一个类用来存放生成验证码的代码。

这里我类的名字叫 ValidateCode

生成验证码（ValidateCode）类的代码：

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Web;

namespace NewWeb.Common
{
    public class ValidateCode
    {
            public ValidateCode()
            {
            }
            /// <summary>
            /// 验证码的最大长度
            /// </summary>
            public int MaxLength
            {
                get { return 10; }
            }
            /// <summary>
            /// 验证码的最小长度
            /// </summary>
            public int MinLength
            {
                get { return 1; }
            }
            /// <summary>
            /// 生成验证码
            /// </summary>
            /// <param name="length">指定验证码的长度</param>
            /// <returns></returns>
            public string CreateValidateCode(int length)
            {
                int[] randMembers = new int[length];
                int[] validateNums = new int[length];
                string validateNumberStr = "";
                //生成起始序列值
                int seekSeek = unchecked((int)DateTime.Now.Ticks);
                Random seekRand = new Random(seekSeek);
                int beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000);
                int[] seeks = new int[length];
                for (int i = 0; i < length; i++)
                {
                    beginSeek += 10000;
                    seeks[i] = beginSeek;
                }
                //生成随机数字
                for (int i = 0; i < length; i++)
                {
                    Random rand = new Random(seeks[i]);
                    int pownum = 1 * (int)Math.Pow(10, length);
                    randMembers[i] = rand.Next(pownum, Int32.MaxValue);
                }
                //抽取随机数字
                for (int i = 0; i < length; i++)
                {
                    string numStr = randMembers[i].ToString();
                    int numLength = numStr.Length;
                    Random rand = new Random();
                    int numPosition = rand.Next(0, numLength - 1);
                    validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1));
                }
                //生成验证码
                for (int i = 0; i < length; i++)
                {
                    validateNumberStr += validateNums[i].ToString();
                }
                return validateNumberStr;
            }
            /// <summary>
            /// 创建验证码的图片
            /// </summary>
            /// <param name="context">要输出到的page对象</param>
            /// <param name="validateNum">验证码</param>
            public void CreateValidateGraphic(string validateCode, HttpContext context)
            {
                Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 22);
                Graphics g = Graphics.FromImage(image);
                try
                {
                    //生成随机生成器
                    Random random = new Random();
                    //清空图片背景色
                    g.Clear(Color.White);
                    //画图片的干扰线
                    for (int i = 0; i < 25; i++)
                    {
                        int x1 = random.Next(image.Width);
                        int x2 = random.Next(image.Width);
                        int y1 = random.Next(image.Height);
                        int y2 = random.Next(image.Height);
                        g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
                    }
                    Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));
                    LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
                     Color.Blue, Color.DarkRed, 1.2f, true);
                    g.DrawString(validateCode, font, brush, 3, 2);
                    //画图片的前景干扰点
                    for (int i = 0; i < 100; i++)
                    {
                        int x = random.Next(image.Width);
                        int y = random.Next(image.Height);
                        image.SetPixel(x, y, Color.FromArgb(random.Next()));
                    }
                    //画图片的边框线
                    g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                    //保存图片数据
                    MemoryStream stream = new MemoryStream();
                    image.Save(stream, ImageFormat.Jpeg);
                    //输出图片流
                    context.Response.Clear();
                    context.Response.ContentType = "image/jpeg";
                    context.Response.BinaryWrite(stream.ToArray());
                }
                finally
                {
                    g.Dispose();
                    image.Dispose();
                }
            }
            /// <summary>
            /// 得到验证码图片的长度
            /// </summary>
            /// <param name="validateNumLength">验证码的长度</param>
            /// <returns></returns>
            public static int GetImageWidth(int validateNumLength)
            {
                return (int)(validateNumLength * 12.0);
            }
            /// <summary>
            /// 得到验证码的高度
            /// </summary>
            /// <returns></returns>
            public static double GetImageHeight()
            {
                return 22.5;
            }



            //C# MVC 升级版
            /// <summary>
            /// 创建验证码的图片
            /// </summary>
            /// <param name="containsPage">要输出到的page对象</param>
            /// <param name="validateNum">验证码</param>
            public byte[] CreateValidateGraphic(string validateCode)
            {
                Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 22);
                Graphics g = Graphics.FromImage(image);
                try
                {
                    //生成随机生成器
                    Random random = new Random();
                    //清空图片背景色
                    g.Clear(Color.White);
                    //画图片的干扰线
                    for (int i = 0; i < 25; i++)
                    {
                        int x1 = random.Next(image.Width);
                        int x2 = random.Next(image.Width);
                        int y1 = random.Next(image.Height);
                        int y2 = random.Next(image.Height);
                        g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
                    }
                    Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));
                    LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
                     Color.Blue, Color.DarkRed, 1.2f, true);
                    g.DrawString(validateCode, font, brush, 3, 2);
                    //画图片的前景干扰点
                    for (int i = 0; i < 100; i++)
                    {
                        int x = random.Next(image.Width);
                        int y = random.Next(image.Height);
                        image.SetPixel(x, y, Color.FromArgb(random.Next()));
                    }
                    //画图片的边框线
                    g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                    //保存图片数据
                    MemoryStream stream = new MemoryStream();
                    image.Save(stream, ImageFormat.Jpeg);
                    //输出图片流
                    return stream.ToArray();
                }
                finally
                {
                    g.Dispose();
                    image.Dispose();
                }
            }
        }
    
}

这时需要在程序中引入两个命名空间 System.Drawing和System.Web。

完成之后到LoginController控制器里面去新建一个ActionResult   就叫ValidateCode 用于生成验证码。（这里要先对NewWeb.Common引用）

生成验证码代码如下:

 public ActionResult ValidateCode()
        {
            Common.ValidateCode validateCode = new Common.ValidateCode();
            string code = validateCode.CreateValidateCode(4); //生成的验证码4个长度
            Session["validateCode"] = code;
            byte[] buffer = validateCode.CreateValidateGraphic(code);//创建验证码图片
            return File(buffer, "image/jpeg");//返回图片
        }

到Login视图里面的index页面去把img的src补充为：

 <tr>
                    <td style="20px"></td>
                    <td><img id="image" src="/Login/ValidateCode/?id=1" style="float: left; height: 24px;" /></td>
                    <td><a href="javascript:void(0)" onclick="changeCheckCode();return false;">看不清，换一张</a></td>
                </tr>

就可以看到页面上面显示出来验证码

下面要做的就是点击切换验证码，这是通过js实现的代码

 <script type="text/javascript">
        $(function () {
           
            initWin();  //初始化登录窗体
            changeCheckCode();  //切换验证码
        });
        function initWin() {
            $("#win").window({
                title: "登录",
                 400,
                height: 270,
                collapsible: false,
                minimizable: false,
                maximizable: false,
                closable: false,
                modal: true,
                resizable: false,
            });
            
        }
        //切换验证码
        function changeCheckCode() {
            $("#changeVcode").click(function () {
                $("#image").attr("src", $("#image").attr("src") + 1);
            });
        }
    </script>