C#验证码

窗体中，需要自己增加的控件：

一个picturebox控件pbVerifyCode，

一个按钮butUpdateVerifyCode（看不清楚，换一张图）；

其它代码可复制使用。  

 

 

  public partial class FrmLogin : Form     {         //随机码的长度         private const int iVerifyCodeLength = 6;         //随机码         private String strVerifyCode = "";

        public FrmLogin()         {             InitializeComponent();             UpdateVerifyCode();         }

        //更新验证码         private void UpdateVerifyCode()         {             strVerifyCode = CreateRandomCode(iVerifyCodeLength);             CreateImage(strVerifyCode);         }

        private string CreateRandomCode(int iLength)         {             int rand;             char code;             string randomCode = String.Empty;

            //生成一定长度的验证码             System.Random random = new Random();             for (int i = 0; i < iLength; i++)             {                 rand = random.Next();

                if (rand % 3 == 0)                 {                     code = (char)('A' + (char)(rand % 26));                 }                 else                 {                     code = (char)('0' + (char)(rand % 10));                 }

                randomCode += code.ToString();             }             return randomCode;         }

        ///  创建随机码图片         private void CreateImage(string strVerifyCode)         {             try             {                 int iRandAngle = 45;    //随机转动角度                 int iMapWidth = (int)(strVerifyCode.Length * 21);                 Bitmap map = new Bitmap(iMapWidth, 28);     //创建图片背景                                  Graphics graph = Graphics.FromImage(map);                 graph.Clear(Color.AliceBlue);//清除画面，填充背景                 graph.DrawRectangle(new Pen(Color.Black, 0), 0, 0, map.Width - 1, map.Height - 1);//画一个边框                 graph.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;//模式

                Random rand = new Random();

                //背景噪点生成                 Pen blackPen = new Pen(Color.LightGray, 0);                 for (int i = 0; i < 50; i++)                 {                     int x = rand.Next(0, map.Width);                     int y = rand.Next(0, map.Height);                     graph.DrawRectangle(blackPen, x, y, 1, 1);                 }

                //验证码旋转，防止机器识别                 char[] chars = strVerifyCode.ToCharArray();//拆散字符串成单字符数组

                //文字距中                 StringFormat format = new StringFormat(StringFormatFlags.NoClip);                 format.Alignment = StringAlignment.Center;                 format.LineAlignment = StringAlignment.Center;

                //定义颜色                 Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };                 //定义字体                 string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };

                for (int i = 0; i < chars.Length; i++)                 {                     int cindex = rand.Next(7);                     int findex = rand.Next(5);

                    Font f = new System.Drawing.Font(font[findex], 13, System.Drawing.FontStyle.Bold);//字体样式(参数2为字体大小)                     Brush b = new System.Drawing.SolidBrush(c[cindex]);

                    Point dot = new Point(16, 16);                                          float angle = rand.Next(-iRandAngle, iRandAngle);//转动的度数

                    graph.TranslateTransform(dot.X, dot.Y);//移动光标到指定位置                     graph.RotateTransform(angle);                     graph.DrawString(chars[i].ToString(), f, b, 1, 1, format);                                          graph.RotateTransform(-angle);//转回去                     graph.TranslateTransform(2, -dot.Y);//移动光标到指定位置                 }                 pbVerifyCode.Image = map;

                             }             catch (ArgumentException)             {                 MessageBox.Show("创建图片错误。");             }         }

 

        private void butUpdateVerifyCode_Click(object sender, EventArgs e)         {             UpdateVerifyCode();

        }