【下载文档:  ASP.NET技巧：教你制做Web实时进度条.txt 】

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ASP.NET技巧：教你制做Web实时进度条
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：

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 description for _Default. ///

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); } /**////

/// Required method for Designer support - do not modify /// the contents of this method with the code editor. ///

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++) { System.Threading.Thread.Sleep(1000); //设置每个阶段的state值，用来显示当前的进度 Session["State"] = i+1; } //任务结束 Session["State"] = 100; } public static void OpenProgressBar(System.Web.UI.Page Page) { StringBuilder sbScript = new StringBuilder(); sbScript.Append("\n"); Page.RegisterClientScriptBlock("OpenProgressBar", sbScript.ToString()); } private void Button1_Click(object sender, System.EventArgs e) { System.Threading.Thread thread=new System.Threading.Thread(new System.Threading.ThreadStart(LongTask)); thread.Start(); Session["State"]=1; OpenProgressBar(this.Page); } }}新建一个进度条页面Progress.aspx客户端：在head中加入

服务器端：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;namespace WebProgressBar{ /**////

/// Summary description for Progress. ///

public class Progress : System.Web.UI.Page { protected System.Web.UI.WebControls.Label lblMessages; protected System.Web.UI.WebControls.Panel panelProgress; protected System.Web.UI.WebControls.Panel panelBarSide; protected System.Web.UI.WebControls.Label lblPercent; private int state = 0; private void Page_Load(object sender, System.EventArgs e) { // Put user code to initialize the page here if(Session["State"]!=null) { state = Convert.ToInt32(Session["State"].ToString()); } else { Session["State"]=0; } if(state>0&&state<=10) { this.lblMessages.Text = "Task undertaking!"; this.panelProgress.Width = state*30; this.lblPercent.Text = state*10 + "%"; Page.RegisterStartupScript("",""); } if(state==100) { this.panelProgress.Visible = false; this.panelBarSide.Visible = false; this.lblMessages.Text = "Task Completed!"; Page.RegisterStartupScript("",""); } } 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); } /**////

/// Required method for Designer support - do not modify /// the contents of this method with the code editor. ///

private void InitializeComponent() { this.Load += new System.EventHandler(this.Page_Load); } #endregion }}