WinForm Timers not firing

Andrew Fraser TDK 101

I have an application that has been running for the last couple of years without problem.
I had reason to make some additions to the application recently and it completely stopped working.
On closer investigation, NONE of the timers that I have dropped onto my main application form are firing even after setting their Enabled property to true !
My application uses half a dozen timers on the form for different tasks and none of them are now working.
I have no explanation as to why this is happening other than suspecting that a .NET Framework update broke something but there does not seem to be any 'noise' on the internet suggesting no one else has this issue.

Does anyone have any thoughts what might be happening ?

Andy

David Lowndes 4,711 Reputation points

2021-04-08T10:30:31.67+00:00

If you create a new project as a sanity test, can you reproduce the problem?
Andrew Fraser TDK 101 Reputation points

2021-04-08T10:44:05.417+00:00

David,

Thanks for your quick reply.
Yes, if I create a new project the timer works as expected.
But if I drop a new timer on my exiting applications main form, set it to enabled by default and put a breakpoint on the timer tick method, it does not get called !
It is quite bizarre !

Andy
Andrew Fraser TDK 101 Reputation points

2021-04-08T10:53:00.07+00:00

Okay, this must be something I have done - though I can't think what I could do to kill all timers on my form but...
The timer handler is called once but after I initialise my application never again so something I do somewhere seems to have killed the timers.
What I don't understand is all their Enabled properties are set to true and their intervals are not messed up so I am at a bit of a loss :-(

Will need to dig deeper into my initialisation code !

Andy
Andrew Fraser TDK 101 Reputation points

2021-04-08T10:59:41.89+00:00
Okay, this gets stranger !
In my initialisation code, I load the customers logo from the embedded resource.

this._customerLogo = this.LoadImageFromEmbeddedResource( "logo.png" );

LoadImageFromEmbeddedResource looks like this:

private Image LoadImageFromEmbeddedResource( string rscname ) { System.Reflection.Assembly thisExe = System.Reflection.Assembly.GetExecutingAssembly(); System.IO.Stream file = thisExe.GetManifestResourceStream("App.Images." + rscname); return Image.FromStream( file ); }

If I comment out the this._customerLogo, the timer keeps firing and if I put that line back in, the timer stops firing after this code is called !

If anyone can explain this I would be delighted to hear it !

Andy
David Lowndes 4,711 Reputation points

2021-04-08T11:04:03.113+00:00

I can't imagine why that should have an effect, but do you need a using on that Stream object?
Viorel 111.8K Reputation points

2021-04-08T11:10:31.15+00:00

Does it succeed (without throwing an uncaught exception)?
Andrew Fraser TDK 101 Reputation points

2021-04-08T11:12:12.753+00:00

David,

Good point, I guess the stream will not be disposed when the method exits.
Unfortunately, putting the stream into a using statement does not fix my timer issue :-(

Thanks for your comments though - very much appreciated.

Andy
Andrew Fraser TDK 101 Reputation points

2021-04-08T11:12:54.253+00:00

Yes, it does succeed as I see my customer logo on screen.

Thanks.

Andy
Viorel 111.8K Reputation points

2021-04-08T11:20:21.99+00:00

According to documentation, “You must keep the stream open for the lifetime of the Image”, therefore the file variable must be moved to class (form) and kept open and undisposed. This is to fix possible problems with the image. Probably it does not affect the timers.

Check if the timers work if you return from Tick handlers without executing the operations.
Andrew Fraser TDK 101 Reputation points

2021-04-08T11:27:20.597+00:00
Interesting, I guess because I did not wrap the stream in a using it effectively kept it open for the lifetime of the application.
I am sure in other applications I have written I wrap the stream in the using statement and let the stream close once I have the image and I have not had problems - I will take more care to keep the stream open in the future !

Just to confirm the issue with the timers, I dropped a new timer on my form and simple update the application title bar in the handler:

private void timer1_Tick( object sender, EventArgs e ) { this.Text = DateTime.Now.ToLongTimeString(); timer1.Enabled = true; }

So really simple code which executes up until I read the image from the embedded resource then stops updating. Even if I take the code in the handler out, the handler is not being called.

Andy
David Lowndes 4,711 Reputation points

2021-04-08T11:29:28.813+00:00

Is your application busy - preventing the timers from executing?
Viorel 111.8K Reputation points

2021-04-08T11:32:35.607+00:00

Does it work if you comment this._customerLogo, but still call LoadImageFromEmbeddedResource, and then also comment some of its lines?
Andrew Fraser TDK 101 Reputation points

2021-04-08T11:33:34.52+00:00

David,

No, the application is not busy - with this simple test the application is not doing anything at all !

Andy
Andrew Fraser TDK 101 Reputation points

2021-04-08T11:37:00.057+00:00
Good shout !
If I call LoadImageFromEmbeddedResource but don't load the return value into _customerLogo, the time keeps firing :-)
_customerLogo is defined as:

/// <summary> /// The logo that is displayed on the ribbon bar. /// </summary> private readonly Image _customerLogo;

Andy
Viorel 111.8K Reputation points

2021-04-08T11:43:31.11+00:00

If even this._customerLogo = new Bitmap(32, 32) affects the timers, then show some details about further usage of _customerLogo.
Andrew Fraser TDK 101 Reputation points

2021-04-08T11:53:41.073+00:00

this._customerLogo = new Bitmap(32, 32) still kills the timer !!
This code is nearly 3 years old and has been used by the customer for almost that long !
something has changed somewhere recently that has caused this problem to appear.

I appreciate your help on this 👍

Andy
Andrew Fraser TDK 101 Reputation points

2021-04-08T12:01:16.837+00:00

This must be something to do with the WinForms control company I use.
The customer image is used by the controls company's RibbonBar component via the its custom paint event.
If I put back the code

this._customerLogo = this.LoadImageFromEmbeddedResource( "logo.png" );

But comment out where the image is rendered on the ribbon bar the timer keeps firing.
I think I am going to escalate this issue to the controls vendor and see what they say.

Andy
David Lowndes 4,711 Reputation points

2021-04-08T12:40:02.567+00:00

Have you checked with Spy++ to see if there are messages ongoing (that you might not be aware of)?
Andrew Fraser TDK 101 Reputation points

2021-04-08T13:05:11.03+00:00

David,

If the 3rd party controls vendor cannot shed any light on this issue then I will dust of Spy++ and see if it can tell me anthing.

Best Regards

Andy

Accepted answer

Andrew Fraser TDK 101 Reputation points

2021-04-09T10:25:16.537+00:00

Solved !
It turns out I had carelessly called Refresh on my ribbon bar control within the ribbon bar paint handler that causing recursive paint messages to be generated.
If I had followed David's suggestion to use Spy++ might have seen all these messages flying about !
Surprised this did not cause additional problems.

Thanks to both of you for your suggestions - much appreciated.

Andy
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1 person found this answer helpful.
David Lowndes 4,711 Reputation points

2021-04-09T10:35:37.107+00:00

Glad you've got there in the end. :)
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WinForm Timers not firing

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