Object Reference Bug

Hi team, 

I'm experiencing another issue with my control. Steps to reproduce the bug on my branch (happens on the others too): 

1) Create new task in a column
2) Move task to any other column
3) Try to delete the task

If you clone, or download this branch: https://github.com/hjohnson12/KanbanBoardUWP/tree/update_cardsdesign

Image: 

That should reproduce the bug. I get a System.NullReferenceException: 'Object reference not set to an instance of an object.' and I've stepped through each part of my code and everything seems to be correct. When I look at the local $exception, I see things showing up for SfKanban DLL's and files, so I'm wondering if that has something to do with it, maybe? 

In the image included with this thread, you'll see at the point where it breaks is at Tasks.Remove(model). The previous line gets the previousCount, which is 1, as expected. Once it goes to the next line (line 278), Tasks.Count still holds 1, but once the line is executed it breaks; BUT, if you hover over Tasks, you'll see that its count is 0 now. 

So, it removes it, but then gets a null reference exception saying instance not set, when my model is definitely initialized and has data in it 😄

It's odd, I know. If you need any additional context, please let me know. I tried for a few days debugging, setting breakpoints, testing locals and watches, adding extra code, and nothings solved it. Hoping your team will notice something I wont :-) 

I can verify that it is happening on every single one of my branches as well, including master (although master is out of date at the moment, it's still doing it with those old changes before I made a bunch of new ones). The branch I linked in the above post is the most up to date. Here is the values when the exception happens: 

 

This is also the stack trace for the above exception. 

Hi Hunter,

 

We were able to reproduce the reported issue in the provided sample. But, we have checked the same issue with separate sample and the reported issue is not reproduced in our sample. We have attached the tested sample. Now, we are checking the sample you have provided. So, we need one more day to validate the sample, we will update you the status in one business day on July 31^st, 2019.

 

TestedSample: https://www.syncfusion.com/downloads/support/directtrac/general/ze/KanbanSamp262787148

 

Regards,

Lakshmi R.

 

Hi Lakshmi, 

Thank you for your reply! :) 

Hi Muneesh, 

I appreciate checking this out! If I find anything further procedure wise, I'll make sure to let you know!

I'm curious though, were you able to find the root of the problem? I checked many times but was unable to 🤔 (Besides that null error. Just didn't know what was throwing it)

Hi Muneesh, 

Thank you for you and your teams help investigating these issues. I'm sorry we've came across many issues along the way with the database and collection updating issues, hoping us solving them will help others out in the future! 

Also, once this patch is released, as well as the one from thread 145994, I should be nearly done with the app and issues will be all solved. Hope I haven't been a pain! :) 

Awesome! Thanks so much team. I really appreciate it. 

Hi Muneesh!

Thank you for the update. After including the latest nuget package today and doing further testing/additions, I have not ran into the bug again! 😁

I thank you and your team very much for your support, samples provided, and patience with the bugs and questions for my application. It's been extremely helpful and if I have any additional questions upon finishing it I will definitely reach out. 

Again, thank you very much for your support!!