RadzenGrid virtualization - no rows with LoadData

Radzen.Blazor Components
1

Hi,

I'm trying to enable virtualization on the radzengrid (Radzen Blazor 4.1.9)

If I have LoadData handler declared, no data appears in the grid. If the handler is removed, I can see all the bound records.

Any particular reason? Am I missing something?

A.

2

Most probably you’ve not set Count - check our demo for reference.

3

thank you for a speedy response!

Thanks for pointing me to the Count property setting on the grid.
Now I have the records rendered in the grid, but, out of 500 records I'm only getting 20.
The LoadData callback is triggered but what I can see in the args parameter is that Skip is always set to 0 and args.Top set to 18

Not quite sure what I'm doing wrong.

   <RadzenDataGrid TItem="RowViewModel"
                    ExpandMode="DataGridExpandMode.Single"
                    AllowVirtualization="true"
                    Data="@_rowViewModels"
                    LoadData="@LoadData"
                    Count="@_recordCount"
                    AllowFiltering="true">
... ... ... ... 

    private IEnumerable<RowViewModel> _rowViewModels;
    private int _recordCount;
    
    private void LoadData(LoadDataArgs args)
    {
        if (!string.IsNullOrEmpty(args.Filter))
        {
            ViewModel.ApplyFilter(args.Filter);
        }
        else
        {
            ViewModel.ApplyFilter(string.Empty);
        }
        _rowViewModels = ViewModel.FilteredRows
            .Skip(args.Skip.Value)
            .Take(args.Top.Value)
            .ToList();
        _recordCount = _rowViewModels .Count();
    }

I assume this might be related to this issue ?
datagrid-virtualization-loaddata bug with many rows · Issue #653 · radzenhq/radzen-blazor · GitHub

4

The Count should be set to total records count not the count of requests items. You’ve missed also to specify height. I strongly recommend you to check carefully our demo.

5

Thank you once again. When trying to set the filter on the grid following exception is thrown and grid becomes unresponsive. This happens when I enabled filtering and started filtering the set..

WARN 2023-01-26 18:08:40.2641 [ 32] Server.Circuits.RemoteRenderer | Unhandled exception rendering component: The current thread is not associated with the Dispatcher. Use InvokeAsync() to switch execution to the Dispatcher when triggering rendering or component state.
System.InvalidOperationException: The current thread is not associated with the Dispatcher. Use InvokeAsync() to switch execution to the Dispatcher when triggering rendering or component state.
at Microsoft.AspNetCore.Components.Web.Virtualization.Virtualize1.BuildRenderTree(RenderTreeBuilder builder) at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, Exception& renderFragmentException) ERROR 2023-01-26 18:08:40.2923 [ 32] ts.Server.Circuits.CircuitHost | Unhandled exception in circuit 'PUFMRwEGCP0oQ-IbdTFmKYTFCj99SQvJAK1bcZNPdPU'. System.InvalidOperationException: The current thread is not associated with the Dispatcher. Use InvokeAsync() to switch execution to the Dispatcher when triggering rendering or component state. at Microsoft.AspNetCore.Components.Web.Virtualization.Virtualize1.BuildRenderTree(RenderTreeBuilder builder)
at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, Exception& renderFragmentException)