前端：
<tr> <td style="height: 20px" ><div align="center"> 验证码：</div></td> <td align="left" style=" 277px; height: 20px;" ><asp:TextBox ID="txtCode" runat="server" Height="25px" Width="112px"></asp:TextBox></td> <td align="center" style="height: 20px" ><asp:Image ID="Image1" runat="server" Width="100px" BorderColor="Gray" BorderWidth="1px" Height="32px" ImageUrl="~/Image.aspx" /></td> <td align="center" style="height: 20px" ><asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ControlToValidate="txtCode" Display="Dynamic" ErrorMessage="请输入验证码" ForeColor="DimGray" Font-Size="10pt">*</asp:RequiredFieldValidator> </td> </tr>
Image.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Image.aspx.cs" Inherits="Image" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>无标题页</title> </head> <body> <form id="form1" runat="server"> <div> </div> </form> </body> </html>
Image.aspx.cs
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; using System.IO; using System.Drawing.Imaging; using System.Drawing; public partial class Image : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { string tmp = RndNum(Convert.ToInt16(6)); Session["verify"] = tmp; ValidateCode(tmp); } private void ValidateCode(string VNum) { Bitmap Img = null; Graphics g = null; MemoryStream ms = null; int gheight = VNum.Length * 9; Img = new Bitmap(gheight, 18); g = Graphics.FromImage(Img); //背景颜色 g.Clear(Color.WhiteSmoke); //文字字体 Font f = new Font("Tahoma", 10); //文字颜色 SolidBrush s = new SolidBrush(Color.Red); g.DrawString(VNum, f, s, 3, 3); ms = new MemoryStream(); Img.Save(ms, ImageFormat.Jpeg); Response.ClearContent(); Response.ContentType = "image/Jpeg"; Response.BinaryWrite(ms.ToArray()); g.Dispose(); Img.Dispose(); Response.End(); } private string RndNum(int VcodeNum) { string MaxNum = ""; string MinNum = ""; for (int i = 0; i < 5; i++)//这里的4是验证码的位数 { MaxNum = MaxNum + "5"; } MinNum = MaxNum.Remove(0, 1); Random rd = new Random(); string VNum = Convert.ToString(rd.Next(Convert.ToInt32(MinNum), Convert.ToInt32(MaxNum))); return VNum; } }