image.aspx.cs

oa办公系统

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.Drawing.Imaging;
using System.IO;
using System.Drawing; 

public partial class image : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        this.GenImg(this.GenCode(4));
        ////将验证码存储到session中，以便需要时进行验证
        Session["image"] = this.GenCode(4);
       // string aa = Session["image"].ToString();
    }
    //任意产生4个验证码
    private string GenCode(int num) 
    {    
        //定义一个验证码数组
        string[] source ={ "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" }; 
        string code = ""; 
        Random rd = new Random(); 
        for (int i = 0; i < num; i++) 
        { 
            code += source[rd.Next(0, source.Length)]; 
        } 
        return code; 
    }     
    //生成图片  
    private void GenImg(string code)   
    {
        //定义一个画板
        Bitmap myPalette = new Bitmap(60, 20);
        //在画板上定义绘图的实例   
        Graphics gh = Graphics.FromImage(myPalette);
        //定义一个矩形
        Rectangle rc = new Rectangle(0, 0, 60, 20);
        //填充矩形  
        gh.FillRectangle(new SolidBrush(Color.White), rc);
        //在矩形内画出字符串 
        gh.DrawString(code, new Font("宋体", 16), new SolidBrush(Color.Black), rc);
        //将图片显示出来   
        myPalette.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
        gh.Dispose();         
        myPalette.Dispose();     
    }      
}