SfComboBox Throws Exception in 25.1

[Mike-E]

When expanding a ComboBox with Virtualization enabled, an exception is thrown in 25.1:

```

System.ArgumentNullException: Value cannot be null. (Parameter 'source')

   at System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)

   at System.Linq.Enumerable.Cast[TResult](IEnumerable source)

   at Syncfusion.Blazor.Data.BlazorAdaptor.ProcessResponse[T](Object data, DataManagerRequest queries)

   at Syncfusion.Blazor.DataManager.ExecuteQuery[T](DataManagerRequest queries)

   at Syncfusion.Blazor.DataManager.ExecuteQuery[T](Query query)

   at Syncfusion.Blazor.DropDowns.SfDropDownBase`1.ExecuteDataQueryAsync(IEnumerable`1 dataSource, Query query)

   at Syncfusion.Blazor.DropDowns.SfDropDownBase`1.GetDataSourceAsync(IEnumerable`1 dataSource, Query query)

   at Syncfusion.Blazor.DropDowns.SfDropDownBase`1.RenderItemsAsync(IEnumerable`1 listData)

   at Syncfusion.Blazor.DropDowns.SfDropDownList`2.CreatePopupAsync(Boolean isCustomFilter)

   at Syncfusion.Blazor.DropDowns.SfDropDownList`2.ShowPopup()

   at Syncfusion.Blazor.DropDowns.SfDropDownList`2.DropDownClickHandlerAsync()

   at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)

   at Syncfusion.Blazor.Inputs.Internal.SfInputBase.InvokeMouseIconHandler(MouseEventArgs args, String iconName)

   at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)

```

This does not occur in 24.x

Unfortunately I cannot offer a simple solution that demonstrates this problem.  I am experiencing this in my primary solution and am having to use 24.x in the meantime.

[Mike-E]

Here is what 24.x looks like:

https://i.imgur.com/EtGWBXH.gif

In 25.1, there are "no records" (or empty) even as I can see the results in debugger:

Recording of what I see here:

https://i.imgur.com/1lVLKlL.gif

The exception above is created when the dropdown pop-up is displayed twice.  This does not happen in 24.x

[Priyanka Karthikeyan]

Hi Mike-E,

We have considered the reported issue "When enabling virtualization and binding a custom adapter, the data is not loading properly in the combobox popup" as a bug from our end and the fix for the issue will be included on Upcoming weekly release, which is scheduled at the end of May 2024.

 

Now you can track the status of the reported issue through the feedback below,

 

Feedback link:https://www.syncfusion.com/feedback/56818/when-enabling-virtualization-and-binding-a-custom-adapter-the-data-is-not-loading

 

Disclaimer: “Inclusion of this solution in the weekly release may change due to other factors including but not limited to QA checks and works reprioritization.”

Regards,

Priyanka K

 

[Mike-E]

WOW!  Thank you so much @Priyanka and team!  I was really worried about tracking this one down as it was very difficult for me to reproduce simply.  I am so very glad you were able to spot what occurred here.  THANK YOU!

[Priyanka Karthikeyan]

Hi Mike-E,

 

We would like to inform you that we have resolved the reported issue "When enabling virtualization and binding a custom adapter, the data is not loading properly in the combobox popup" in our latest version 25.2.7. Therefore, we recommend that you update your package to the latest version to resolve the current problem. 

 

Root cause:
 

After validating the issue, it was observed that upon closing and reopening the popup, the virtual track height is not updated correctly. This discrepancy occurs because the value of the mainDataCount variable, which is crucial for updating the virtual track height, is not being updated appropriately.

 

Regards,

Priyanka K

[Mike-E]

Thank you again Priyanka and team for all your effort out there!  I am so very happy you were able to determine the root cause for this issue as I was really struggling with how I would be able to reproduce this for you.  I appreciate all that you do over there!

[Priyanka Karthikeyan]

Hi Mike-E,

Thank you for the update. Please get back to us if you need any further assistance.

Regards,

Priyanka K