<TelerikGrid 
                         OnRead="@OnGridRead"
                         Data="Data"
                         Pageable="true"
                         PageSize="10"
                         Width="100%"
                         Sortable="true"
                         Navigable="true"
                         Groupable="true"
                         SelectionMode="GridSelectionMode.Single"
                         SortMode="@SortMode.Single"
                         FilterMode="@GridFilterMode.FilterMenu"
                         Resizable="true"
                         OnRowClick="OnRowClickCallback"
                         Reorderable="true"
                         AutoGenerateColumns="true">

                <TelerikGrid Data="@vm.Model.CO_DetailsList"
                     @ref="grid"
                     EditMode="@Telerik.Blazor.GridEditMode.Incell">
            
                    <GridColumns>
                        <GridColumn Field="@nameof(CO_Details.Seg0)" Title="Fund" Width="70px">
                            <EditorTemplate>
                                <TelerikComboBox Data="@vmSeg0.Model"
                                             TextField="Value"
                                             ValueField="Value"
                                             TItem="GL_Seg0RO"
                                             TValue="string"
                                             @bind-Value="vm.Model.CO_DetailsList[index].Seg0">
                                    <ComboBoxSettings>
                                        <ComboBoxPopupSettings MaxHeight="@seg0CmbHeight"/>
                                    </ComboBoxSettings>
                                </TelerikComboBox>
                            </EditorTemplate>
                        </GridColumn>
                    </GridColumns>
                </TelerikGrid>

<TelerikForm @ref="@FormRef"
             Model="@EntityModel"
             OnSubmit="@OnSubmitHandler"
             >
    <FormValidation>
        <DataAnnotationsValidator />
    </FormValidation>
    <FormItems>
        <CascadingValue Name="TheForm" Value="@FormRef">
            @foreach (var form_item in FormItemCollection)
            {
                <DynamicComponent Type="@form_item.ComponentType" Parameters="@form_item.Parameters" />
            }
        </CascadingValue>
    </FormItems>
    <FormButtons>
        <TelerikButton 
                      ButtonType="@ButtonType.Submit"  
                       Enabled="@SaveEnabled"
                       ThemeColor="primary">Speichern</TelerikButton>
    </FormButtons>

</TelerikForm>

protected override void OnAfterRender(bool firstRender)
    {
        if (firstRender)
        {
            FormRef.EditContext.OnFieldChanged += EditContext_OnFieldChanged;
        }
        base.OnAfterRender(firstRender);
    }

    private void EditContext_OnFieldChanged(object sender, FieldChangedEventArgs e)
    {
        SaveEnabled = true;
        StateHasChanged();
    }

<TelerikGrid Data="@Customers"
                 Pageable="false"
                 Sortable="true"
                 ScrollMode="@GridScrollMode.Virtual"
                 OnRead="@ReadItems"
                 LoadGroupsOnDemand="true"
                 FilterMode="@GridFilterMode.FilterRow"
                 PageSize="20">
        <GridColumns>
            <GridColumn Field="Number" Title="Nr" Width="150px" />
            <GridColumn Field="Zip" Title="ZIP"></GridColumn>
            <GridColumn Field="City" Title="City"></GridColumn>
            <GridColumn Field="FirstName" Title="First"></GridColumn>
            <GridColumn Field="LastName" Title="Last"></GridColumn>
        </GridColumns>
    </TelerikGrid>

public async Task<DataEnvelope<CustomerDTO>> FetchPagedData(DataSourceRequest dataSourceRequest)
{
        var result = await Http.PostAsJsonAsync(ApiRoutes.Customer.POST_Lazy(), dataSourceRequest);
        var fullList = await result.Content.ReadFromJsonAsync<DataEnvelope<CRMCustomerDTO>>();
        return fullList;
 }

protected async Task ReadItems(GridReadEventArgs args)
{
        var dataResult = await FetchPagedData(args.Request);

        if (args.Request.Groups.Count > 0)
        {
            args.Data = dataResult.GroupedData.Cast<object>().ToList();
        }
        else
        {
            args.Data = dataResult.CurrentPageData.Cast<object>().ToList();
        }

        args.Total = dataResult.TotalItemCount;

        StateHasChanged();
}

[HttpPost("Lazy")]
public async Task<DataEnvelope<CustomerDTO>> GetLazy([FromBody] DataSourceRequest dataSourceRequest)
{
            DataEnvelope<CustomerDTO> dataEnvelope = new();

            var customers = await _context.Customer
                                            .Include(c => c.Address)
                                            .ToListAsync();

            var customerDTOs = _mapper.Map<List<CustomerDTO>>(customers);


            DataSourceResult result = customerDTOs.ToDataSourceResult(dataSourceRequest);

            if (dataSourceRequest.Groups.Count > 0)
            {
                dataEnvelope = new DataEnvelope<CustomerDTO>
                {
                    GroupedData = result.Data.Cast<AggregateFunctionsGroup>().ToList(),
                    TotalItemCount = result.Total
                };
            }
            else
            {
                dataEnvelope = new DataEnvelope<CustomerDTO>{
                    CurrentPageData = result.Data.Cast<CustomerDTO>().ToList(),
                    TotalItemCount = result.Total
                };
            }

            return dataEnvelope;
}