473,714 Members | 2,395 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Update text property of asp label control on a webform

Hi,
Is there a way to update the text of an asp:label on a webform without
refreshing the entire page? What is called by button clicks and other
events that refresh a webform control?

See the example WebForm1.aspx and WebForm1.aspx.c s code below:

WebForm1.aspx
=============== =============== =============== ==========

<%@ Page language="c#" Codebehind="Web Form1.aspx.cs"
AutoEventWireup ="false" Inherits="updat eLabelTest.WebF orm1" %>

<HTML>
<HEAD>
<title>WebForm1 </title>
</HEAD>
<body >

<form id="Form1" method="post" runat="server">
<asp:Button id=Button1 runat="server" Text="Button"></asp:Button>
<asp:Label id=Label1 runat="server"> Label</asp:Label>
<br>
<asp:Button id=Button2 runat="server" Text="Button"></asp:Button>
<asp:Label id=Label2 runat="server"> Label</asp:Label>
</form>

</body>
</HTML>


WebForm1.aspx.c s
=============== =============== =============== ==========

using System;
using System.Collecti ons;
using System.Componen tModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.Sess ionState;
using System.Web.UI;
using System.Web.UI.W ebControls;
using System.Web.UI.H tmlControls;

namespace updateLabelTest
{
/// <summary>
/// Summary description for WebForm1.
/// </summary>
public class WebForm1 : System.Web.UI.P age
{
protected System.Web.UI.W ebControls.Labe l Label1;
protected System.Web.UI.W ebControls.Butt on Button1;
protected System.Web.UI.W ebControls.Labe l Label2;
protected System.Web.UI.W ebControls.Butt on Button2;

int nTotalSeconds = 0;
int nIntervalInSeco nds = 5;

private void Page_Load(objec t sender, System.EventArg s e)
{
// Put user code to initialize the page here
}

#region Web Form Designer generated code
override protected void OnInit(EventArg s e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeCompo nent();
base.OnInit(e);
}

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeCompo nent()
{
this.Button1.Cl ick += new System.EventHan dler(this.Butto n1_Click);
this.Button2.Cl ick += new System.EventHan dler(this.Butto n2_Click);
this.Load += new System.EventHan dler(this.Page_ Load);

}
#endregion

// Option 1: Simply update the label Text within a loop
private void Button1_Click(o bject sender, System.EventArg s e)
{
// Trying to update the text of the asp:label every second.
// Label1.Text does not get updated until
// after Button1_Click returns.
// Thus, i = 4 shows up, but we never see i = 1, 2, or 3.
//
// I realize this could be done via javascript using:
// <meta http-equiv="refresh" content="5">
// However, I have a more complex C# website application that
// requires updating from within the asp.net CodeBehind.
for( int i=1; i < 5; i++ )
{
Label1.Text = i.ToString();
System.Threadin g.Thread.Sleep( 1000 );
}
}

// Option 2: Update using a System Timer
private void Button2_Click(o bject sender, System.EventArg s e)
{
// I'd prefer to use a Timer and update based on the Timer Interval.
// I don't understand why Label2.Text never gets updated despite
// MyTimerEventHan dler firing even 5 seconds.
System.Timers.T imer myTimer = new System.Timers.T imer();
myTimer.Elapsed += new System.Timers.E lapsedEventHand ler(
MyTimerEventHan dler );
myTimer.Interva l = nIntervalInSeco nds*1000;
myTimer.Start() ;
}

private void MyTimerEventHan dler( object source,
System.Timers.E lapsedEventArgs e )
{
nTotalSeconds += nIntervalInSeco nds;
Label2.Text = "timer " + nTotalSeconds.T oString();
}

}
}

Nov 19 '05 #1
1 9223
You need to realize that the threading you're doing in your C# code is on
the server. So while your serevr code is doing Thread.Sleep, the browser
is still waiting for the page to be rendered. This is not the approach you
want. If you want the browser to come back to the server every 5 seconds,
then, as you mentioned, you'll need the meta-refresh or you'll need to do
something in the browser with window.setinter val. The code you write in the
page doesn't render back to the browser until it's completely processed,
so the browser's just going to wait. Also, if you spin up another thread
and then try to do something there, the main thread that was rendering your
page will have completed, so the secondary thread will be out of context
if it tries to emit anything else.

-Brock
DevelopMentor
http://staff.develop.com/ballen
Hi,
Is there a way to update the text of an asp:label on a webform without
refreshing the entire page? What is called by button clicks and other
events that refresh a webform control?
See the example WebForm1.aspx and WebForm1.aspx.c s code below:

WebForm1.aspx
=============== =============== =============== ==========
<%@ Page language="c#" Codebehind="Web Form1.aspx.cs"
AutoEventWireup ="false" Inherits="updat eLabelTest.WebF orm1" %>

<HTML>
<HEAD>
<title>WebForm1 </title>
</HEAD>
<body >
<form id="Form1" method="post" runat="server">
<asp:Button id=Button1 runat="server" Text="Button"></asp:Button>
<asp:Label id=Label1 runat="server"> Label</asp:Label>
<br>
<asp:Button id=Button2 runat="server" Text="Button"></asp:Button>
<asp:Label id=Label2 runat="server"> Label</asp:Label>
</form>
</body>
</HTML>
WebForm1.aspx.c s
=============== =============== =============== ==========
using System;
using System.Collecti ons;
using System.Componen tModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.Sess ionState;
using System.Web.UI;
using System.Web.UI.W ebControls;
using System.Web.UI.H tmlControls;
namespace updateLabelTest
{
/// <summary>
/// Summary description for WebForm1.
/// </summary>
public class WebForm1 : System.Web.UI.P age
{
protected System.Web.UI.W ebControls.Labe l Label1;
protected System.Web.UI.W ebControls.Butt on Button1;
protected System.Web.UI.W ebControls.Labe l Label2;
protected System.Web.UI.W ebControls.Butt on Button2;
int nTotalSeconds = 0;
int nIntervalInSeco nds = 5;
private void Page_Load(objec t sender, System.EventArg s e)
{
// Put user code to initialize the page here
}
#region Web Form Designer generated code
override protected void OnInit(EventArg s e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeCompo nent();
base.OnInit(e);
}
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeCompo nent()
{
this.Button1.Cl ick += new System.EventHan dler(this.Butto n1_Click);
this.Button2.Cl ick += new System.EventHan dler(this.Butto n2_Click);
this.Load += new System.EventHan dler(this.Page_ Load);
}
#endregion
// Option 1: Simply update the label Text within a loop
private void Button1_Click(o bject sender, System.EventArg s e)
{
// Trying to update the text of the asp:label every second.
// Label1.Text does not get updated until
// after Button1_Click returns.
// Thus, i = 4 shows up, but we never see i = 1, 2, or 3.
//
// I realize this could be done via javascript using:
// <meta http-equiv="refresh" content="5">
// However, I have a more complex C# website application that
// requires updating from within the asp.net CodeBehind.
for( int i=1; i < 5; i++ )
{
Label1.Text = i.ToString();
System.Threadin g.Thread.Sleep( 1000 );
}
}
// Option 2: Update using a System Timer
private void Button2_Click(o bject sender, System.EventArg s e)
{
// I'd prefer to use a Timer and update based on the Timer
Interval.
// I don't understand why Label2.Text never gets updated despite
// MyTimerEventHan dler firing even 5 seconds.
System.Timers.T imer myTimer = new System.Timers.T imer();
myTimer.Elapsed += new System.Timers.E lapsedEventHand ler(
MyTimerEventHan dler );
myTimer.Interva l = nIntervalInSeco nds*1000;
myTimer.Start() ;
}
private void MyTimerEventHan dler( object source,
System.Timers.E lapsedEventArgs e )
{
nTotalSeconds += nIntervalInSeco nds;
Label2.Text = "timer " + nTotalSeconds.T oString();
}
}
}


Nov 19 '05 #2

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

9
4775
by: Pam Ammond | last post by:
I need the code to update the database when Save is clicked and a text field has changed. This should be very easy since I used Microsoft's wizards for the OleDBAdapter and OleDBConnection, and DataSet; and all I'm doing is showing one record in text fields, allowing the user to modify the text fields, and then updating the database again when the user clicks the Save button. The fields already show the correct data record since I have...
0
1767
by: compuglobalhypermeganetz0r | last post by:
I am having trouble getting an adapter to update my access database, it gives the error Syntax error in INSERT INTO statement. for Line 98: Adapter.Update(WineDS, "tblWines") Below is my code: <%@ Control Explicit="True" Language="VB" Debug="True" %> <%@ Import Namespace="System.Data" %> <%@ Import Namespace="System.Data.OleDb" %>
7
2930
by: Mike Casey | last post by:
Hello all, I have ASP.NET label controls tied to a datasource (so text will vary in length depending on the record). In IE everything looks great--text is wrapped if needed. In Netscape and Opera, the text extends horizontally and does not wrap. Any ideas would be most appreciated! Thanks,
4
2008
by: CaptRR | last post by:
I think this is the right group to post to, so here goes. My problem is this, I cannot update the datarow to save my life. Been on this for 2 days now, and still am no closer to figuring it out than I was before. I'm basicly taking date from some text boxes, trying to put them into a datarow and using that datarow to update the database, but its not working. The btn_update is where I am sending the information back to the addclient...
4
7230
by: Terry | last post by:
Hello, I am trying to get a response for an .aspx page in my current project (same virtual directory) by using WebRequest.GetResponse but I keep getting a exception with "500 Internal server error" in the exception message. I am able to do this fine with another .aspx page that has no code-behind. The page that has code-behind throws the exception. What I am doing is getting the .aspx response, reading the stream, replacing
0
2207
by: Metal2You | last post by:
I'm working on an ASP.NET 2.0 application in Visual Studio 2005 that accesses a Sybase database back end. We're using Sybase SQL Anywhere 9.0.2.3228. I have installed and registered the Sybase .NET 2.0 DataProvider (iAnywhere.Data.AsaClient.dll) into the GAC so it can be used in the ProviderName property of a SQLDataSource and loads properly at run time. The application I'm writing is a bit more complex than the example I'm about to...
8
5367
by: =?Utf-8?B?R3JlZyBMYXJzZW4=?= | last post by:
I'm trying to figure out how to modify a panel (panel1) from a backgroundworker thread. But can't get the panel to show the new controls added by the backgroundwork task. Here is my code. In this code there is a panel panel1, that I populate with a lable in the foreground. Then when I click on "button1" a backgroundworker thread in async mode is started. When the backgoundworker thread completes the thread returns a panel to populate...
12
13250
by: vbnewbie | last post by:
I am having problems accessing properties of dynamically generated objects in VB2005. Can someone please help? In a nutshell: My app creates an equal number of checkboxes and labels that share the same Tag number. (I thought it might help) The checkboxes name is a concatenation of "chkCancel" and a number that represents the order in which they were created: chkCancel0 (Tag = 0) chkCancel1 (Tag = 1)
2
8618
by: Wayne Brantley | last post by:
If you expose a public property of a usercontrol that accesses an object on the user control it will give a null reference exception when you wrap that in an update panel. Others are having the same problem. Here is a complete example: http://forums.asp.net/thread/1555836.aspx Related to this: (But I am not doing dynamic user control creation) http://www.eightpence.com/null-controls-inside-of-an-updatepanel-in-aspnet-atlas/
0
8808
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...
1
9077
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
9021
tracyyun
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
0
7954
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
1
6637
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms. Adolph will...
0
5951
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
4465
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
0
4727
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
3
2113
bsmnconsultancy
by: bsmnconsultancy | last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.