c#验证码

 

C# 验证码操作

 

 

public partial class 验证码 : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

{

//产生随机数

        string tmp = RndNum(5).ToUpper();

//用session进行传值

        this.Session["ImageV"] = tmp;

//生产图片

        this.CreateCheckCodeImage(tmp);

    }

//生验证码随即数字+字母组合

    private string RndNum(int VcodeNum)

        string Vchar = "a,b,c,d,e,0,1,2,3,4,5,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,0,1,2,3,4,5,6,7,8,9,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,1,2,3,4,5,6,7,8,9,n,o,p,q,r,s,t,u,v,w,x,y,z";

        string[] VcArray = Vchar.Split(new Char[] { ',' });//将上面的字符串切分成单个字符，数组形式的

        string VNum = "";

        int temp = -1;

        Random rand = new Random();//随即数

        for (int i = 1; i < VcodeNum + 1; i++)

        {

            if (temp != -1)

            {

                rand = new Random(i * temp * unchecked((int)DateTime.Now.Ticks));

            }

            int t = rand.Next(35);

            if (temp != -1 && temp == t)

            {

                return RndNum(VcodeNum);

            }

            temp = t;

            VNum += VcArray[t];

        }

        return VNum;

    }

    //创建验证码背景图片

    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 * 13.0)), 21);

        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, 1);

            //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();

        }

    }

}

 

在第二个页面里拖放一个图片控件，设置一下图片的Url地址，就可以在第二个页面显示出验证码了。

<asp:Image ID="Image1" runat="server" Height="40px" ImageUrl="~/Default.aspx" Width="70px" />