private PreviewSettings _preview;
public Index()
{
    _preview = new PreviewSettings()
    {
        CanPreview = true,
        OpenViewer = OpenViewer
    };
}
            
private async void OpenViewer(ViewerSettings settings)
{
    if (_viewer != null)
    {
	    await _viewer.OpenReport(settings.DocumentInfo.Id);
	    return;
    }
    _viewer = new ReportViewer();
    var initOptions = new InitializationOptions();
    initOptions.ReportID = settings.DocumentInfo.Id;
    await _viewer.Render(JSRuntime, settings.Element, initOptions);
}