asp.net MVC 在Controller控制器中实现验证码输出

   asp.net mvc项目使用到验证码，为了让以前的webform代码能利用上代码经过稍微的改动即可使用代码如下：

using system;
using system.collections.generic;
using system.web;
using system.web.mvc;
using system.web.ui;
using system.web.ui.webcontrols;
using system.drawing;

namespace angel.web.controllers
{
    public class checkcodecontroller : controller
    {
        //
        // get: /checkcode/

        public actionresult index()
        {
            this.createcheckcodeimage(generatecheckcode());
            return view();
        }

        private string generatecheckcode()
        {
            int number;
            char code;
            string checkcode = string.empty;

            system.random random = new random();
            for (int i = 0; i < 5; i++)
            {
                number = random.next();

                if (number % 2 == 0)
                    code = (char)('0' + (char)(number % 10));
                else
                    code = (char)('a' + (char)(number % 26));

                if (code == '0' || code == 'o' || code == 'l' || code == 'i')
                {
                    i = i - 1;
                }
                else
                {
                    checkcode += code.tostring();
                }
            }

            //	response.cookies.add(new httpcookie("checkcode", checkcode));
            session.contents["checkcode"] = checkcode;

            return checkcode;
        }

        private void createcheckcodeimage(string checkcode)
        {
            if (checkcode == null || checkcode.trim() == string.empty)
                return;

            system.drawing.bitmap image = new system.drawing.bitmap((int)math.ceiling((checkcode.length * 12.5)), 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);

                //画图片的背景噪音线
                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 system.drawing.font("arial", 12, (system.drawing.fontstyle.bold | system.drawing.fontstyle.italic));
                system.drawing.drawing2d.lineargradientbrush brush = new system.drawing.drawing2d.lineargradientbrush(new rectangle(0, 0, image.width, image.height), color.blue, color.darkred, 1.2f, true);
                g.drawstring(checkcode, font, brush, 2, 2);

                //画图片的前景噪音点
                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);

                system.io.memorystream ms = new system.io.memorystream();
                image.save(ms, system.drawing.imaging.imageformat.gif);
                response.clearcontent();
                response.contenttype = "image/gif";
                response.binarywrite(ms.toarray());
            }
            finally
            {
                g.dispose();
                image.dispose();
            }
        }

    }
}

　　最后别忘了session的获取设置，需要在global.asax.cs文件中新增如下代码：

        /// <summary>
        /// mvc为了获取session参数
        /// </summary>
        public override void init()
        {
            postauthenticaterequest += (s, e) => httpcontext.current.setsessionstatebehavior(sessionstatebehavior.required);
            base.init();
        }

        void mvcapplication_postauthenticaterequest(object sender, eventargs e)
        {
            httpcontext.current.setsessionstatebehavior(sessionstatebehavior.required);
        }

 

 

html页面代码：

views 
html代码
<img name="img1" id="img1" style="position:absolute;top:5px;right:36px!important;z-index:1000;" alt="单击图片刷新验证码" src="checkcode/index" 
onclick="javasccript:reloadimage('checkcode/index');" />
<script type="text/javascript">

function reloadimage(url) {
document.getelementbyid(“img1”).src = url + ‘?abc=’ + math.random();
}

   </script>