Hello Viktoras,

Thank you for your effort in providing a runnable example that reproduces the encountered behavior.

With our latest version, we introduced a change for the same scenario. When using grouping and OnRead, casting data to a list of objects (.Cast<object>()) is no longer needed. So, the required modification in the provided example is to remove the Cast<object> from the OnRead handler.

f (args.Request.Groups.Count > 0)
        {
            var data = GroupDataHelpers.DeserializeGroups<WeatherForecast>(result.GroupedData);
            args.Data = data.ToList();

            args.AggregateResults = GridAggregateResult.ConvertToAr(result.GridAggregateResults);

        }
        else
        {
            args.Data = result.CurrentPageData.ToList();
        }

With the above in mind, I'm marking the bug report item as "Declined".

I hope the provided information serves you well.

Regards,
Tsvetomir
Progress Telerik

Hello Viktoras,

Thank you for the provided screenshot.

I tried to recreate the behavior from the screenshot on my side within this REPL sample app (the REPL platform is a WASM application). As a result, the grouping is working as expected. This leads me to think that, I'm missing something from the actual configuration.

As a next step, please modify the REPL example to reproduce the behavior and send it back to me for inspection. This will help me see the behavior first-hand and troubleshoot it further. For now, I'm changing the item status to "Need More Info".

I look forward to your reply.

Regards,
Tsvetomir
Progress Telerik