Silverlight验证码生成

• 在Silverlight的登录页面中经常用到输入验证码，怎么生成的呢，其实和.NET生成差不多，以下简单介绍一种：

  1、在Silverlight项目下建立一个类IndentifyCodeClass.cs文件

      1）、首先注意添加引用 using System.Windows.Media.Imaging;

      2）、添加一个用来产生验证码的方法
          public String CreateIndentifyCode(int count)
          {
              String allchar = "1,2,3,4,5,6,7,8,9,A,a,B,b,C,c,D,d,E,e,F,f," +
                  "G,g,H,h,I,i,J,j,K,k,L,l,M,m,N,n,O,o,P,p,Q,q,R,r,S,s," +
                  "T,t,U,u,V,v,W,w,X,x,Y,y,Z,z";
              String[] allchararray = allchar.Split(',');
              String randomcode = "";
              int temp = -1;
              Random rand = new Random();
              for (int i = 0; i < count; i++)
              {
                  if (temp != -1)
                  {
                      rand = new Random(i * temp * ((int)datetiR_362_11845@e.Now.Ticks));
                  }
                  int t = rand.Next(61);
                  if (temp == t)
                  {
                      return CreateIndentifyCode(count);
                  }
                  temp = t;
                  randomcode += allchararraY[t];
              }
              return randomcode;
          }

      3）、添加一个方法，用来产生验证码的背景噪声图片
          Random r = new Random(datetiR_362_11845@e.Now.Millisecond);
          public void CreatImage(String Text,Image imgsource,int iw,int ih)
          {
              Grid Gx = new Grid();
              Canvas cv1 = new Canvas();
              for (int i = 0; i < 6; i++)
              {
                  Polyline p = new Polyline();
                  for (int ix = 0; ix < r.Next(3,6); ix++)
                  {
                      p.points.Add(new Point(r.NextDouble() * iw,
                          r.NextDouble() * ih));
                  }
                  byte[] Buffer = new byte[3];
                  r.NextBytes(Buffer);
                  SolidColorBrush SC = new SolidColorBrush(Color.FromArgb(255,
                      Buffer[0],Buffer[1],Buffer[2]));
                  p.stroke = Sc;
                  p.strokeThickness = 0.5;
                  cv1.Children.Add(p);
              }
              Canvas cv2 = new Canvas();
              int y = 0;
              int lw = 6;
              double w = (iw - lw) / Text.Length;
              int h = (int)ih;
              foreach (char x in Text)
              {
                  byte[] Buffer = new byte[3];
                  r.NextBytes(Buffer);
                  SolidColorBrush SC = new SolidColorBrush(Color.FromArgb(255,Buffer[2]));
                  TEXTBlock t = new TextBlock();
                  t.TextAlignment = TextAlignment.Center;
                  t.FontSize = r.Next(h - 3,h);
                  t.Foreground = Sc;
                  t.Text = x.ToString();
                  t.Projection = new PlaneProjection()
                  {
                      RotationX = r.Next(-30,30),
                      RotationY = r.Next(-30,
                      RotationZ = r.Next(-10,10)
                  };
                  cv2.Children.Add(t);
                  Canvas.SetLeft(t,lw / 2 + y * w);
                  Canvas.SetTop(t,0);
                  y++;
              }
              Gx.Children.Add(cv1);
              Gx.Children.Add(cv2);
              WriteableBitmap W = new WriteableBitmap(Gx,new TransformGroup());
              W.Render(Gx,new TransformGroup());
              imgsource.source = W;
          }

  2、在登录页面的UserControl_Loaded事件中添加如下代码即可：

        IndentifyCodeClass code = new IndentifyCodeClass();

        String generatedCode =  code.CreateIndentifyCode(6);
        code.CreatImage(generatedCode,checkCodeImage,150,30);

  3、获取用户在文本框中输入的验证码，然后和产生的验证码进行比较验证。

     ....

       String indentifyCode = this.tbIndentifyCode.Text.trim();

       if(generatedCode !=indentifyCodE)

       {

            messageBox.Show("验证码输入错误！");

            this.tbIndentifyCode.Focus(); //输入焦点聚焦

       }

问题： 3中的generatedCode是局部变量