C#中实现验证码的参考代码

生成验证码的方法

using System;

using System.Collections;

using System.Configuration;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Drawing;

using System.Drawing.Imaging;

using System.IO;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;



public partial class YanZhengMa : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

        //  首先调用RndNum函数生成4位数字的验证码

        string str_ValidateCode = RndNum(4);

        //  然后把它保存在用于验证的Session里边

        Session["imageCode"] = str_ValidateCode;

        //调用CreateImage函数，把验证码绘制到图片中

        CreateImage(str_ValidateCode);

    }

    private string RndNum(int VcodeNum)

    {

        string Vchar = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p" +

         ",q,r,s,t,u,v,w,x,y,z";

        string[] VcArray = Vchar.Split(new Char[] { ',' });

        string VNum = "";

        //int temp = -1;

        Random rand = new Random();

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

        {



            int t = rand.Next(36);



            VNum += VcArray[t];

        }

        return VNum;

    }

    //生成随机颜色



    private Color GetRandomColor()

    {

        Random RandomNum_First = new Random((int)DateTime.Now.Ticks);

        //  对于C#的随机数，没什么好说的

        System.Threading.Thread.Sleep(RandomNum_First.Next(50));

        Random RandomNum_Sencond = new Random((int)DateTime.Now.Ticks);

        //  为了在白色背景上显示，尽量生成深色

        int int_Red = RandomNum_First.Next(256);

        int int_Green = RandomNum_Sencond.Next(256);

        int int_Blue = (int_Red + int_Green > 400) ? 0 : 400 - int_Red - int_Green;

        int_Blue = (int_Blue > 255) ? 255 : int_Blue;

        return Color.FromArgb(int_Red, int_Green, int_Blue);

    }

    public void CreateImage(string str_ValidateCode)

    {

        int int_ImageWidth = str_ValidateCode.Length * 13;

        Random newRandom = new Random();

        //  图高20px

        Bitmap theBitmap = new Bitmap(int_ImageWidth, 20);

        Graphics theGraphics = Graphics.FromImage(theBitmap);

        //  白色背景

        theGraphics.Clear(Color.White);

        //  灰色边框

        theGraphics.DrawRectangle(new Pen(Color.LightGray, 1), 0, 0, int_ImageWidth - 1, 19);

        //  10pt的字体

        Font theFont = new Font("Arial", 10);

        for (int int_index = 0; int_index < str_ValidateCode.Length; int_index++)

        {

            string str_char = str_ValidateCode.Substring(int_index, 1);

            Brush newBrush = new SolidBrush(GetRandomColor());

            Point thePos = new Point(int_index * 13 + 1 + newRandom.Next(3), 1 + newRandom.Next(3));

            theGraphics.DrawString(str_char, theFont, newBrush, thePos);

        }

        //  将生成的图片发回客户端

        MemoryStream ms = new MemoryStream();

        theBitmap.Save(ms, ImageFormat.Jpeg);



        Response.ClearContent(); //需要输出图象信息 要修改HTTP头 

        Response.ContentType = "image/Png";

        Response.BinaryWrite(ms.ToArray());

        theGraphics.Dispose();

        theBitmap.Dispose();

        Response.End();

    }



}





 

在前台调用的时候的部分代码

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