日期:2010-09-30  浏览次数:20448 次

网上已经有很多Web进度条的例子,但是很多都是估算时间,不能正真反应任务的真实进度。我自己结合多线程和ShowModalDialog制做了一个实时进度条,原理很简单:使用线程开始长时间的任务,定义一个Session,当任务进行到不同的阶段改变Session的值,线程开始的同时使用ShowModalDialog打开一个进度条窗口,不断刷新这个窗口获取Session值,反应出实时的进度。下面就来看看具体的代码:(文章结尾处下载源代码)

先新建一个Default.aspx页面,
客户端代码:

<body MS_POSITIONING="GridLayout">
    <form id="Form1" method="post" runat="server">
            <br>
            <br>
            <asp:Button id="Button1" runat="server" Text="Start Long Task!"></asp:Button>
    </form>
</body>
服务器端代码:
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Text;

namespace WebProgressBar
{
    /**//// <summary>
    /// Summary description for _Default.
    /// </summary>
    public class _Default : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.Button Button1;
   
        private void Page_Load(object sender, System.EventArgs e)
        {
            // Put user code to initialize the page here
        }

        Web Form Designer generated code#region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: This call is required by the ASP.NET Web Form Designer.
            //
            InitializeComponent();
            base.OnInit(e);
        }
       
        /**//// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {   
            this.Button1.Click += new System.EventHandler(this.Button1_Click);
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion

        private void LongTask()
        {
            //模拟长时间任务
            //每个循环模拟任务进行到不同的阶段
            for(int i=0;i<11;i++)
            {
   &