Textbox locks up using textchanged event

Question

0.00/5 (No votes)

See more:

I'm using Visual Studio 2015, webform, C#
I've got a textbox which the user enters a numeric value, upon tabbing out it fires the following code

protected void txtAsset_TextChanged(object sender, EventArgs e)
    {
        lblSuccessful.Text = string.Empty;
        txtAsset.Focus();
        string input = txtAsset.Text;
        if (!Regex.IsMatch(input, @"^[0-9]\d*"))
        {
            lblSuccessful.CssClass = "ErrorMessage";
            lblSuccessful.Text = "You have input invalid criteria";
            txtAsset.Text = string.Empty;
            txtAsset.Focus();
        }
        else
        {
          Execute Retrieval of record
        }

It works perfectly however, when the user types another number in sometimes you can type into the textbox othertimes it locks up, you can't delete the value or type anything.

Auto postback is on.

Any assistance appreciated

What I have tried:

I've removed the validation and it still happens, is this a Microsoft Bug

Posted 21-Sep-17 3:09am

Member 12573955

Updated 24-Sep-17 21:36pm

Add a Solution

Comments

Karthik_Mahalingam 21-Sep-17 9:50am

try inside an update panel, you shall achieve the same in JavaScript as well, which will eliminate the unnecessary round trips.

3 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2017-09-21T04:03:00

Look at your code: every time the txtAsset TextBox Text property is changed, you get a TextChanged event fired. And what do you do inside the event? Change the Text property of the same TextBox. Which causes another event to be fired. Which changes the Text, which causes an event, which ... you get the picture. Take the change to the textbox out, and your problem will disappear.

Member 12573955 · Answer 2 · 2017-09-24T21:21:00

Solution 2

Hi Many thanks for your reply, I don't follow you.

My event only fires upon tabbing out of the textbox, if the validation is successful it enters the code to retrieve the record from the database, have stripped out most of the code and removed the validation and it still causes issues.

Posted 24-Sep-17 21:21pm

Member 12573955

Graeme_Grant · Answer 3 · 2017-09-24T21:36:00

Set a breakpoint at the start of the code inside the event and step through the code. You will see exactly what is happening.

If you are not familiar with the debugger, here is a video that will get you started quickly: Basic Debugging with Visual Studio 2010 - YouTube[^]

And here is how to fix the StackOverflow exception:

C#

private bool isChanging;

protected void txtAsset_TextChanged(object sender, EventArgs e)
{
    // are we in the middle of chaning the txtAsset.Text property?
    // Yes, don't process the change that the code is in the middle
    //      of changing
    if (isChanging) return;
    
    // No? Okay, set the falg and make the change...
    isChanging = true;

    lblSuccessful.Text = string.Empty;
    txtAsset.Focus();
    string input = txtAsset.Text;
    if (!Regex.IsMatch(input, @"^[0-9]\d*"))
    {
        lblSuccessful.CssClass = "ErrorMessage";
        lblSuccessful.Text = "You have input invalid criteria";
        
        // this next line fires the txtAsset.TextChanged event...
        txtAsset.Text = string.Empty;
        
        txtAsset.Focus();
    }
    else
    {
      Execute Retrieval of record
    }
    
    //We are all done...
    isChanging = false;
}

Textbox locks up using textchanged event

3 solutions

Solution 1

Solution 2

Solution 3

Add your solution here

Preview 0