问题
I've seen this particular problem posted multiple times but none of the solutions I've seen actually accomplish what I'm trying to do.
I have an ASP.NET page with an UpdatePanel on it. In the UpdatePanel is a button and a multiline textbox. The button's click event disables the button and enters a processing loop that updates the Text property of the TextBox multiple times. But, of course, the TextBox is not actually updated until the loop completes.
I've seen suggestions to add a Timer control to the page and I've tried that. But the Timer's Tick doesn't fire during until the loop is complete so it's no use!
Does ANYONE have a working solution for this? I need a page that allows the user to click a button to initiate a process that processes multiple records in a database and gives updates to the user indicating each record processed.
Here's my page code:
<!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></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<br />
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Always">
<ContentTemplate>
<asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />
<br />
<asp:TextBox ID="TextBox1" runat="server" Height="230px" TextMode="MultiLine"
Width="800px"></asp:TextBox>
</ContentTemplate>
</asp:UpdatePanel>
</div>
</form>
</body>
</html>
Here's my code-behind:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace UpdatePanel
{
public partial class Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
Button1.Enabled = false;
for (int x = 1; x < 6; x++)
{
ViewState["progress"] += "Beginning Processing Step " + x.ToString() + " at " + DateTime.Now.ToLongTimeString() + "..." + System.Environment.NewLine;
System.Threading.Thread.Sleep(1000); //to simulate a process that takes 1 second to complete.
ViewState["progress"] += "Completed Processing Step " + x.ToString() + " at " + DateTime.Now.ToLongTimeString() + System.Environment.NewLine;
TextBox1.Text = ViewState["progress"].ToString();
}
}
}
}
If I simply set the VewState value in the loop and then add a Timer that sets the TextBox Text property to the ViewState value, that code never fires until the loop is completed.
回答1:
Well, I finally found the answer in this post. I've adjusted my own code accordingly (with a few tweaks) and it works perfectly now.
Here's my page code:
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="UpdatePanel.Default" %>
<!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></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
<asp:Timer runat="server" ID="Timer1" Interval="1000" Enabled="false" ontick="Timer1_Tick" />
<br />
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Always">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="Timer1" EventName="Tick" />
</Triggers>
<ContentTemplate>
<asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />
<br />
<asp:TextBox ID="TextBox1" runat="server" Height="250px" TextMode="MultiLine"
Width="800px"></asp:TextBox>
</ContentTemplate>
</asp:UpdatePanel>
</div>
</form>
</body>
</html>
Here's my code-behind:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Threading;
namespace UpdatePanel
{
public partial class Default : System.Web.UI.Page
{
protected static string content;
protected static bool inProcess = false;
protected static bool processComplete = false;
protected static string processCompleteMsg = "Finished Processing All Records.";
protected void Page_Load(object sender, EventArgs e){ }
protected void Button1_Click(object sender, EventArgs e)
{
Button1.Enabled = false;
Timer1.Enabled = true;
Thread workerThread = new Thread(new ThreadStart(ProcessRecords));
workerThread.Start();
}
protected void ProcessRecords()
{
inProcess = true;
for (int x = 1; x <= 5; x++)
{
content += "Beginning Processing Step " + x.ToString() + " at " + DateTime.Now.ToLongTimeString() + "..." + System.Environment.NewLine;
Thread.Sleep(1000);
content += "Completed Processing Step " + x.ToString() + " at " + DateTime.Now.ToLongTimeString() + System.Environment.NewLine + System.Environment.NewLine;
}
processComplete = true;
content += processCompleteMsg;
}
protected void Timer1_Tick(object sender, EventArgs e)
{
if (inProcess)
TextBox1.Text = content;
int msgLen = processCompleteMsg.Length;
if (processComplete && TextBox1.Text.Substring(TextBox1.Text.Length - processCompleteMsg.Length) == processCompleteMsg) //has final message been set?
{
inProcess = false;
Timer1.Enabled = false;
Button1.Enabled = true;
}
}
}
}
回答2:
Are you looking for this
protected void Button1_Click(object sender, EventArgs e)
{
Button1.Enabled = false;
for (int x = 1; x < 6; x++)
{
ViewState["progress"] += "Beginning Processing Step " + x.ToString() + " at " + DateTime.Now.ToLongTimeString() + "..." + System.Environment.NewLine;
System.Threading.Thread.Sleep(1000); //to simulate a process that takes 1 second to complete.
ViewState["progress"] += "Completed Processing Step " + x.ToString() + " at " + DateTime.Now.ToLongTimeString() + System.Environment.NewLine;
TextBox1.Text += ViewState["progress"].ToString();
}
}
来源：https://stackoverflow.com/questions/27583227/updating-asp-net-updatepanel-during-processing-loop