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  • 生成验证码(纯数字)

    前几天写了个数字与字母混合的验证码技术,今天写个纯数字的验证码。这里先写个类

    CheckCode.cs

    using System;
    using System.Data;
    using System.Configuration;
    using System.Web;
    using System.Web.Security;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    using System.Web.UI.WebControls.WebParts;
    using System.Web.UI.HtmlControls;
    
    using System.Drawing;
    
    /// <summary>
    /// CheckCode 的摘要说明
    /// </summary>
    public class CheckCode
    {
        public CheckCode()
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }
        public static void DrawImage()
        {
            CheckCode img = new CheckCode();
            HttpContext.Current.Session["CheckCode"] = img.RndNum(4);
            img.checkCodes(HttpContext.Current.Session["CheckCode"].ToString());
        }
        /// <summary>
        /// 生成验证图片
        /// </summary>
        /// <param name="checkCode">验证字符</param>
        private void checkCodes(string checkCode)
        {
            int iwidth = (int)(checkCode.Length * 13);
            System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 23);
            Graphics g = Graphics.FromImage(image);
            g.Clear(Color.White);
            //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" };
            Random rand = new Random();
            //随机输出噪点
            for (int i = 0; i < 50; i++)
            {
                int x = rand.Next(image.Width);
                int y = rand.Next(image.Height);
                g.DrawRectangle(new Pen(Color.LightGray, 0), x, y, 1, 1);
            }
    
            //输出不同字体和颜色的验证码字符
            for (int i = 0; i < checkCode.Length; i++)
            {
                int cindex = rand.Next(7);
                int findex = rand.Next(5);
    
                Font f = new System.Drawing.Font(font[findex], 10, System.Drawing.FontStyle.Bold);
                Brush b = new System.Drawing.SolidBrush(c[cindex]);
                int ii = 4;
                if ((i + 1) % 2 == 0)
                {
                    ii = 2;
                }
                g.DrawString(checkCode.Substring(i, 1), f, b, 3 + (i * 12), ii);
            }
            //画一个边框
            g.DrawRectangle(new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1);
    
            //输出到浏览器
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
            HttpContext.Current.Response.ClearContent();
            //Response.ClearContent();
            HttpContext.Current.Response.ContentType = "image/Jpeg";
            HttpContext.Current.Response.BinaryWrite(ms.ToArray());
            g.Dispose();
            image.Dispose();
        }
    
        /// <summary>
        /// 生成随机的字母
        /// </summary>
        /// <param name="VcodeNum">生成字母的个数</param>
        /// <returns>string</returns>
        private string RndNum(int VcodeNum)
        {
            string Vchar = "0,1,2,3,4,5,6,7,8,9";
            string[] VcArray = Vchar.Split(',');
            string VNum = ""; //由于字符串很短,就不用StringBuilder了
            int temp = -1; //记录上次随机数值,尽量避免生产几个一样的随机数
            //采用一个简单的算法以保证生成随机数的不同
            Random rand = new Random();
            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(VcArray.Length);
                if (temp != -1 && temp == t)
                {
                    return RndNum(VcodeNum);
                }
                temp = t;
                VNum += VcArray[t];
            }
            return VNum;
        }
    }

    再建立一个引用类的页面checkCode.aspx前台不用写东西,后台引用我们创建的类的DrawImage()方法即可。

    using System;
    using System.Data;
    using System.Configuration;
    using System.Collections;
    using System.Web;
    using System.Web.Security;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    using System.Web.UI.WebControls.WebParts;
    using System.Web.UI.HtmlControls;
    
    public partial class checkCode : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            CheckCode.DrawImage();
        }
    }

    下面我们在需要验证码的页面引用checkCode.aspx页面即可。
    前台

                              <asp:TextBox ID="Validator" runat="server" Width="150px" ></asp:TextBox>
                              <img id="Img1" alt="看不清,请点击我!" onclick="this.src=this.src+'?'" src="checkCode.aspx"
                                            style=" 73px; height: 22px" align="left" />
                                   <asp:ImageButton ID="imgBtnLogin" runat="server" ImageUrl="~/Images/Login.GIF" 
                                OnClick="imgBtnLogin_Click" />             

    后台判断

        protected void imgBtnLogin_Click(object sender, ImageClickEventArgs e)
        {
            if(this.Validator.Text==Session["CheckCode"].ToString())
            {
              //。。。。
            }
            else
            {
                Response.Write("<script>alert('验证码输入错误,请重新输入!');Location='MumberValidate.aspx'</script>");
                return;
            }
        }

    以上代码请根据实际情况作适当修改。

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  • 原文地址:https://www.cnblogs.com/52net/p/2538075.html
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