Having both GroupColumnDescriptions and DetailsViewDefinition crashes the application.

[Haywired]

Having both GroupColumnDescriptions and DetailsViewDefinition set inside of a datagrid causes this crash : Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index'). I was able to confirm this by removing either one, and the app would not crash.

If both are not supported together, I do not think it is indicated anywhere in the documentation. 
Only tested on windows, dotnet 10.

I am using 31.2.18 for the nuget.
Files attached are the view model and xaml.

Attachment: DataGridFeatures_f451aeb0.zip

[Muthukumar Madasamy]

Hi Haywired,

We have checked your query at our end, and we are able to replicate that issue at our end. We have considered this as a bug and logged a bug report regarding this in our feedback portal. We will fix the reported issue and include the changes in our upcoming weekly patch release, which is expected to be rolled out on Jan 06, 2026. We will let you know once released, and we appreciate your patience until then. You can also track the status of the bug using the feedback link below.

Feedback Link: 71860

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.

Best Regards,

Muthu Kumar Madasamy.

[Muthukumar Madasamy]

Hi Haywired,

We are glad to inform you that the reported issue regarding the “Application crashes when using both GroupColumnDescriptions and DetailsViewDefinition in SfDataGrid” has been resolved. This fix has been incorporated into our latest weekly NuGet release. To benefit from this fix, we recommend updating your SfDataGrid package to version 32.1.22.

NuGet Gallery | Syncfusion.Maui.DataGrid 32.1.22

Root Cause of the issue:

The TopLevelGroup was not accounting for the additional rows introduced by the DetailsView, leading to mismatched indices in the visual representation. The RelationsCount property was not properly updated when detail views were toggled, which caused inconsistencies in indexing logic and row retrieval.

We thank you for your support and appreciate your patience in waiting for this update. Please get in touch with us if you require any further assistance.

Best Regards,

Muthu Kumar Madasamy.