1，权限的管理系统：开发项目必备的一个的功能；该项目使用 ASP.NET MVC5 SqlServer EF6 IOC容器 BoostStrap

2，登录界面验证码功能实现，整体效果如下；

3，接下来就是代码部分实现，前端页面；

 

 <div class="input-icon"><i class="fa fa-lock"></i>@Html.PasswordFor(m => m.CheckCode, new { @class = "form-control placeholder-no-fix", @autocomplete = "off", @placeholder = "请输入验证码" })@Html.ValidationMessage("CheckCode", new { @style = "color: red" })</div></div><div class="form-group"><img style="border-radius: 7px; height: 40px;" alt="验证码图片" class="img" onclick="refresh(this)" src="/Account/VerifyCode" title="点击刷新"></div>

js代码在页面刷新或者点击验证码时自动生成新的验证码

 <script type="text/javascript">function refresh(obj) {$(obj).attr("src", "/Account/VerifyCode?random=" + Math.random());}</script>

4，控制器代码

  public void VerifyCode(){string code = string.Empty;Bitmap bitmap = VerifyCodeHelper.CreateVerifyCode(out code);base.HttpContext.Session["CheckCode"] = code;bitmap.Save(base.Response.OutputStream, ImageFormat.Gif);base.Response.ContentType = "image/gif";}

5，生成验证码的核心代码 CreateVerifyCode方法如下；

 public class VerifyCodeHelper{public static Bitmap CreateVerifyCode(out string code){//建立Bitmap对象，绘图Bitmap bitmap = new Bitmap(200, 60);Graphics graph = Graphics.FromImage(bitmap);graph.FillRectangle(new SolidBrush(Color.White), 0, 0, 200, 60);Font font = new Font(FontFamily.GenericSerif, 48, FontStyle.Bold, GraphicsUnit.Pixel);Random r = new Random();string letters = "ABCDEFGHIJKLMNPQRSTUVWXYZ0123456789";StringBuilder sb = new StringBuilder();//添加随机的五个字母for (int x = 0; x < 5; x++){string letter = letters.Substring(r.Next(0, letters.Length - 1), 1);sb.Append(letter);graph.DrawString(letter, font, new SolidBrush(Color.Black), x * 38, r.Next(0, 15));}code = sb.ToString();//混淆背景Pen linePen = new Pen(new SolidBrush(Color.Black), 2);for (int x = 0; x < 6; x++)graph.DrawLine(linePen, new Point(r.Next(0, 199), r.Next(0, 59)), new Point(r.Next(0, 199), r.Next(0, 59)));return bitmap;}}

以上就是实现验证码的全部，谢谢！