RadzenDataGrid.Reload() throwing an ArgumentNullException

I've got a blazor web app that uses an API to interact with an SQL database. When I delete the last object in the datagrid's "Data=" collection and perform a RadzenDataGrid.Reload() it throws the exception.

Here's the datagrid item in the Razor Component...

<RadzenDataGrid @ref="objGrid" Data="@objCollection" TItem="ReportObject"....

The objCollection declaration:

List<ReportObject> objCollection = new List();

Here's the method that's throwing the exception...

public async Task DeleteRow(ReportObject repObj)

		if (objCollection.Contains(repObj))
			if (await errorReportEmailDataService.DeleteErrorReportEmailAsync(repObj.id))

			await objGrid.Reload();
			await CancelEdit(repObj);
	catch (Exception ex) 

		objCollection= (await ReportObjectDataService.GetReportObjectsAsync(reportID)).ToList() ?? Enumerable.Empty<ReportObject>().ToList();


I can't follow the Datagrid inline edit example exactly since I'm not using a dbContext directly...

Since the datagrid can handle an empty collection by showing an empty grid I'm not sure where this is falling apart.

I want to add that this code works fine when the result of objCollection.Remove(repObj) doesn't result in an empty List().

Try to debug your application to check what’s null.

I assumed it was the List that's backing the grid. I'll double check.

The exception message is, "Value cannot be null. {Parameter 'source'}".

The source that the exception is identifying is "System.Linq.Queryable"

It's pointing to a line of code in my LoadData method where I run an API call... That might be the issue. I'll reply to the thread when I've tracked it down.

EDIT: My data service was giving me a null rather than an empty collection. The query variable in my LoadData method expects an "AsQueryable()" result and calling "AsQueryable()" against a null value was where my error was occuring. Problem solved after I corrected my dataservice to give me an empty collection.