Why do I have a bug displaying a custom popup in a thread?

Question

0.00/5 (No votes)

See more:

Hi all,

Why do I have a bug displaying a custom popup in a Thread?

I'm using a custom popup that appears in the bottom right-hand corner of the screen and disappears a few seconds later.

But when I try to display this personalized popup in a Thread, it bugs, i.e. I have to click on the desktop for the popup to appear, but without the alert icon and without the alert message. My mouse is on hold and the program no longer responds.

I have no problem displaying a message with "MessageBox".

What's strange is that if I use my "personal popup" and "messageBox" at the same time, my popup is displayed correctly but it doesn't disappear after a few seconds and the program no longer responds.

Do you know what the problem is?
I've searched but haven't found any questions that match my problem.

What I have tried:

Here's the code:

C#

<pre>     
this.ThreadAutoCheck = new Thread((ThreadStart)(async () =>
     {
      TelegramBotService telegramBotService = new 
      TelegramBotService(this.txtTelegramKey.Texts.Trim());
      string chatId = this.txtChannelID.Texts.Trim();
      while (this.ThreadAutoCheck != null)
      {
        try
        {
          List<Position> otherPositions = new List<Position>();
          foreach (string str in lstUID)
          {
            string uid = str;
            List<Position> positions = await apkApi.GetPositions(uid, type);
            if (positions == null || positions.Count == 0)
            {
              this.Alert("No data to display.", FAlert.enmType.Warning);
            }

Posted 8-Jun-23 21:12pm

Anaîs laffont

Updated 9-Jun-23 1:34am

Andre Oosthuizen

v4

Add a Solution

1 solution

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)

Graeme_Grant · Accepted Answer · 2023-06-08T21:49:00

You should always post the error message in your question so we can see what the exact issue is.

At a guess, you are seeing a cross thread exception. This happens when you try to do UI actions from a thread other than the UI Thread. You can check this by setting a breakpoint before doing any UI work, then look at the Thread window to see what thread you are on.

If you are not on the UI thread, then you need to marshal to the UI thread before doing the UI work.

I work with both WPF and WinForms, both do the marshalling differently. So I have a common helper implementation that I use. Here is the helper class:

C#

public static class DispatcherHelper
{
    public static void Execute(Action action)
    {
        // no cross-thread concerns
        if (Application.OpenForms.Count == 0)
        {
            action.Invoke();
			return;
        }

		try
		{
			if (Application.OpenForms[0]!.InvokeRequired)
                // Marshall to Main Thread
				Application.OpenForms[0]?.Invoke(action);
            else
                // We are already on the Main Thread
                action.Invoke();
        }
		catch (Exception)
		{
			// ignore as might be thrown on shutting down
		}
    }
}

Then to use:

C#

DispatcherHelper.Execute(() => 
{
    // do UI work here...
});

So, in your case, I think you would use it like this:

C#

if (positions == null || positions.Count == 0)
{
    DispatcherHelper.Execute(() =>
        this.Alert("No data to display.", FAlert.enmType.Warning));
}