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 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("<script language='JavaScript' type='text/javascript'>\n"); sbScript.Append("<!--\n"); //需要IE5.5以上支持 sbScript.Append("window.showModalDialog('Progress.aspx','','dialogHeight: 100px; dialogWidth: 350px; edge: Raised; center: Yes; help: No; resizable: No; status: No;scroll:No;');\n"); //IE5.5以下使用window.open //sbScript.Append("window.open('Progress.aspx','', 'height=100, width=350, toolbar =no, menubar=no, scrollbars=no, resizable=no, location=no, status=no');\n"); sbScript.Append("// -->\n"); sbScript.Append("</script>\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<base target="_self">
<body MS_POSITIONING="GridLayout"> <form id="Form1" method="post" runat="server"> <asp:Label id="lblMessages" runat="server"></asp:Label> <asp:Panel id="panelBarSide" runat="server" Width="300px" BorderStyle="Solid" BorderWidth="1px" ForeColor="Silver"> <asp:Panel id="panelProgress" runat="server" Width="10px" BackColor="Green"></asp:Panel> </asp:Panel> <asp:Label id="lblPercent" runat="server" ForeColor="Blue"></asp:Label> </form></body>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> /// Summary description for Progress. /// </summary> 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("","<script>window.setTimeout('window.Form1.submit()',100);</script>"); } if(state==100) { this.panelProgress.Visible = false; this.panelBarSide.Visible = false; this.lblMessages.Text = "Task Completed!"; Page.RegisterStartupScript("","<script>window.close();</script>"); } } Web Form Designer generated code }}源代码下载：WebProgressBar.rar
