Why won't my OnTextChanged event fire

Posted on 2014-09-18
Medium Priority
Last Modified: 2014-09-22
Why won't my OnTextChanged event not fire? (VS 2010; C# ASP .NET 4.0)

<asp:TextBox ID="txtToEmailAddresses" runat="server" Width="400px"

    protected void txtToEmailAddresses_TextChanged(object sender, EventArgs e)
        txtSubject.Text = "Completed: " + txtEmpName.Text;
Question by:Michael Sterling
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 5
  • 4
LVL 18

Expert Comment

by:Jerry Miller
ID: 40330871
Are you performing a partial postback in an update panel? You can set the AutoPostBack="true" in the properties for the textbox.

 <asp:TextBox ID="txtToEmailAddresses" runat="server" Width="400px"
                     ontextchanged="txtToEmailAddresses_TextChanged" AutoPostBack="true"/>

Author Comment

by:Michael Sterling
ID: 40330933
ok, that would probably work so i'll give you the points. my current employer is so afraid of anything so "out of the box" as Ajax Tools that they won't want me to use the required toolkit and scriptmanager etc. needed to make this work.
LVL 18

Accepted Solution

Jerry Miller earned 1400 total points
ID: 40331218
You don't necessarily have to use the Ajax Toolkit, but I believe that the textbox needs to be in an UpdatePanel so you can see the change. Here is a good example of what I am talking about:


Without using something like Ajax or Jquery, I am not sure that you can see the updates. I use the toolkit controls all over my applications without any issues and my company is pretty strict on what we can do.

Here a couple of good reads on JavaScript and JQuery:



In JavaScript if you use the __doPostBack() method, make sure that your trigger is updating the UpdatePanel where you control is located.
Free Backup Tool for VMware and Hyper-V

Restore full virtual machine or individual guest files from 19 common file systems directly from the backup file. Schedule VM backups with PowerShell scripts. Set desired time, lean back and let the script to notify you via email upon completion.  


Author Comment

by:Michael Sterling
ID: 40333174
Ok, but for the UpdatePanel with the ContentTemplate control, I definitely will need that AjaxToolkit / and library, right?
LVL 13

Assisted Solution

by:Jitendra Patil
Jitendra Patil earned 600 total points
ID: 40334143
as Jerry already answered your question, just for your update panel clarification

update panel is control provided by asp.net , you don't need any toolkit or library.

 basically it follows the below aspx code pattern

<asp:UpdatePanel ID="UpdatePanel1" UpdateMode="Conditional" runat="server">
     Email:- <asp:TextBox ID="txtToEmailAddresses" runat="server" Width="400px"
Subject :- <asp:TextBox ID="txtSubject" runat="server" width="400px" />
EmpName:- <asp:TextBox ID="txtEmpName" runat="server" width="400px" />

i've also noted that on your text change event you are setting the values of two different textboxes, so please add those textboxes in the same update panel.

hope this helps.

Author Comment

by:Michael Sterling
ID: 40336773
@litendra Patil: Ok, but I do need a scriptmanager tool though, correct?

script manager error

Author Closing Comment

by:Michael Sterling
ID: 40336817
Thanks to all who contributed.
LVL 18

Expert Comment

by:Jerry Miller
ID: 40336853
ScriptManager is part of the System.Web.UI.Control, you won't need to Ajax Toolkit for it. Simply import the System.Web.UI.Control.

In the top of your class add,

Using System.Web.UI.Control

This should make the ScriptManager available.


Author Comment

by:Michael Sterling
ID: 40337445
Thank you. That did work.
LVL 18

Expert Comment

by:Jerry Miller
ID: 40338168
Cool,  always happy to help!

Featured Post

New feature and membership benefit!

New feature! Upgrade and increase expert visibility of your issues with Priority Questions.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

IntroductionWhile developing web applications, a single page might contain many regions and each region might contain many number of controls with the capability to perform  postback. Many times you might need to perform some action on an ASP.NET po…
This article aims to explain the working of CircularLogArchiver. This tool was designed to solve the buildup of log file in cases where systems do not support circular logging or where circular logging is not enabled
In this video, Percona Solution Engineer Rick Golba discuss how (and why) you implement high availability in a database environment. To discuss how Percona Consulting can help with your design and architecture needs for your database and infrastr…
In this video, Percona Solutions Engineer Barrett Chambers discusses some of the basic syntax differences between MySQL and MongoDB. To learn more check out our webinar on MongoDB administration for MySQL DBA: https://www.percona.com/resources/we…
Suggested Courses

765 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question