Draft feature request (copy/paste)

Title: Add per-column value converters (WPF-style) to Telerik Blazor Grid columns

Product: UI for Blazor → Grid
Type: Feature Request

Description:
In Telerik UI for WPF, grid column definitions can reference a converter by name (e.g., IValueConverter) to transform values for display without writing a custom cell template for each column.

In Telerik UI for Blazor Grid, templates are currently the primary way to change how values render in a column (which works, but becomes repetitive across many columns/grids).

Request:
Add a column-level conversion API that allows specifying a converter/formatter function for display (and optionally editing). Example concepts:

• Converter="nameof(MyConverters.StatusToText)"

• or DisplayConverter="(item) => …" / ValueFormatter="Func<TItem, object, string>"

• optionally ConvertBack-like support for editing scenarios (or separate EditConverter)

Why this is needed:

• Reduces repeated <Template> markup for simple formatting/transformations

• Centralizes formatting/conversion logic in reusable code

• Improves maintainability and consistency across grids

• Eases migration for teams coming from Telerik WPF where converters are a common pattern

Use cases:

• Enum/int → user-friendly text

• Boolean → “Yes/No”, icons, badges

• Null/empty → placeholder text

• Code → display name (via lookup)

• Domain-specific formatting shared across many grids

Workarounds today:

• Column <Template> or computed properties (both valid, but not as concise/reusable for large grids)

• Extracting RenderFragments can reduce repetition, but still requires templating infrastructure for what is logically a simple conversion step

Expected behavior:

• Converter applies consistently anywhere the column renders (cell, export if applicable, etc.)

• Works with sorting/filtering in a predictable way (ideally sorting/filtering still uses raw field value unless explicitly configured)

Hello,

seems like the GridToolbar(even the GridToolbarTemplate) in grid is not rendering "GridToolBarOverflowMode.Section". The "Scroll" mode is ok.

Is there any additional setup, or did i missed some setup...?

REPL:

 https://blazorrepl.telerik.com/wqYQvvEq40GkajEZ30

based on:
https://www.telerik.com/blazor-ui/documentation/components/grid/toolbar

some mention about "sections" but it seems for another purpose:

https://www.telerik.com/blazor-ui/documentation/knowledge-base/common-net8-sections

Thanks

Hi,

I would like to have a Expand/Collapse All Grid Groups button in the Grid Header. I know this is possible to do so programmatically outside of the grid but my users want it inside the Grid. 

Thanks,

Humayoon

Description

A column cannot be reordered by dragging beyond the currently visible columns of the Grid. This significantly limits the column reorder functionality only to the visible viewport.

Steps To Reproduce

1. Run this example: https://blazorrepl.telerik.com/QqudFlYZ18zv7Gv547
2. Drag a column header to the right border of the Grid.

Actual Behavior

The Grid does not scroll horizontally while the column is dragged.

Expected Behavior

The Grid scrolls horizontally while dragging the column and allows dropping it beyond the currently visible columns.

Browser

All

Last working version of Telerik UI for Blazor (if regression)

No response

Description

When clicking a Grid row and the Grid is in GridDataLayoutMode.Stacked mode, the RowClick event fires twice.

Steps To Reproduce

1. Run this example: https://blazorrepl.telerik.com/QgkmvDvQ296Ea3Ij28
2. Click a row in the Grid

Actual Behavior

The RowClick event fires twice.

Expected Behavior

The RowClick event fires once.

Browser

All

Last working version of Telerik UI for Blazor (if regression)

No response

I created a subclass of the TelerikGrid to extend the limited built-in search functionality.

To do that, I use the GridStateChanged event to rewrite the SearchFilter: I replace the default filter with a more complex CompositeFilterDescriptor (including highlighting). This works perfectly during normal interaction.

Now I also want the search to be persisted, so that after reloading the page the grid shows the same search again. Saving the grid state is not a problem, but when restoring the saved state during OnStateInit / GridStateInit, the following exception occurs:

Unable to cast object of type 'Telerik.DataSource.CompositeFilterDescriptor' to type 'Telerik.DataSource.FilterDescriptor'.
System.InvalidCastException: Unable to cast object of type 'Telerik.DataSource.CompositeFilterDescriptor' to type 'Telerik.DataSource.FilterDescriptor'.
at Telerik.Blazor.Components.Common.TableGridBase`2.LoadSearchFilter(IFilterDescriptor descriptor)
at Telerik.Blazor.Components.TelerikGrid`1.SetStateInternalAsync(GridState`1 state)
at Telerik.Blazor.Components.TelerikGrid`1.InvokeOnStateInit()
at Telerik.Blazor.Components.TelerikGrid`1.OnParametersSetAsync()
at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
at Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()
at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)
fail: Microsoft.AspNetCore.Components.Server.Circuits.CircuitHost[111]
Unhandled exception in circuit 'MYsaCsOgfpbyHeO0xNFpA7ViPHNUC6rpc1K9eIwVR5Y'.
System.InvalidCastException: Unable to cast object of type 'Telerik.DataSource.CompositeFilterDescriptor' to type 'Telerik.DataSource.FilterDescriptor'.
at Telerik.Blazor.Components.Common.TableGridBase`2.LoadSearchFilter(IFilterDescriptor descriptor)
at Telerik.Blazor.Components.TelerikGrid`1.SetStateInternalAsync(GridState`1 state)
at Telerik.Blazor.Components.TelerikGrid`1.InvokeOnStateInit()
at Telerik.Blazor.Components.TelerikGrid`1.OnParametersSetAsync()
at Microsoft.AspNetCore.Components.ComponentBase.CallStateHasChangedOnAsyncCompletion(Task task)
at Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()
at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)

I also tried saving the search term and the selected columns separately and then restoring the state in OnAfterRender, but at that point the SearchFilter can no longer be set.

Sincerly Daniel

The following KB article shows a workaround for removing the Grid aggregate labels ("Sum" and "Count") from the exported Excel document: https://www.telerik.com/blazor-ui/documentation/knowledge-base/grid-remove-aggregate-labels-in-excel-footr

It would be nice to have this option as a parameter in the Grid. It would allow to toggle on/off this behavior, instead of having to rely on custom code to work around it. 

Or in the OnBeforeExport method, add extra data to GridBeforeExcelExportEventArgs that contains the aggregates so they can be changed.

 private async Task OnBeforeExcelExport(GridBeforeExcelExportEventArgs args)
 {
     await Task.CompletedTask;

     // Loop through all columns and fix the footer aggregate values
     // Replace the default "Sum: 1234.56" text with just the decimal number
     foreach (var column in args.Columns)
     {
         if (column.HasAggregate)
         {
             // Set the number format for the column so Excel treats it as a number
             column.Aggregate.Field.Value == "MyNewValue";
         }
     }
 }

Hello,

we recently updated Telerik.UI.for.Blazor from 9.0.0 to 12.3.0, afterwords we noticed that in several instances where we use the `TelerikGrid` component, keyboard interactions stopped working. Specifically the `@onkeydown` seems to no longer propagate to parent elements of the grid. As this was not mentioned in the Breaking changes for the version 10 or 12 releases we assume this to be a bug.

here a simplified example:

            <div style="padding: 0; width: @(ShowSidePanel ? "65%" : "99%")" tabindex="0" @onkeydown="@(OnKeyPress)">
                <TelerikGrid TItem="IncomingInvoiceGridItemViewModel"
                             @ref="GridRef"
                             Class="admin-grid"
                             Height="@OverviewHeight"
                             RowHeight="50"
                             Pageable="false"
                             PageSize="PageSize"
                             FilterMode="@GridFilterMode.FilterMenu"
                             Sortable="true"
                             Resizable="true"
                             Reorderable="true"
                             ShowColumnMenu="true"
                             ScrollMode="@GridScrollMode.Virtual"
                             SelectionMode="@GridSelectionMode.Single"
                             OnStateInit="@OnStateInit_SetStateAsync"
                             OnStateChanged="@OnStateChanged_SaveStateAsync"
                             SelectedItemsChanged="@OnSelectedItemsChanged_LoadPdf"
                             OnRead="@OnRead_UpdateFilteredItems">
                    <GridSettings>
                        <GridColumnMenuSettings Lockable="false" />
                    </GridSettings>
...
<!-- aggregates, columns and noDataTemplate omitted -->
...
                </TelerikGrid>
            </div>

Implementation / usages of the features did not change, only updates where changes required by the update Telerik.UI.for.Blazor from 9.0.0 to 12.3.0.

These were the dependencies updated alongside the update of Telerik.UI.for.Blazor from 9.0.0 to 12.3.0 :

The Grid's CheckBoxColumn doesn't support the TextAlign property, making it impossible to center the checkbox with just Grid markup, you have to resort to a workaround.

The TextAlign property in other columns causes style="text-align: center" to be added to the underlying table cell.  This would also work for the checkbox column.

See this test:

<table class="table">
    <tr>
        <td class="table-active" style="width: 40px; text-align: center"><input type="checkbox" /> </td>
        <td>test</td>
    </tr>
</table>

Please add the TextAlign property to the CheckboxColumn.

I want to reorder the Grid rows the same way I can reorder the columns - via the keyboard.

For reference: Telerik jQuery Grid drag and drop

Column headers and column data do not match after reordering. 

See this example: https://blazorrepl.telerik.com/GKkFcwlF54CvZoVp34 

1. Reorder Group 1 and Group 2.

2. The column headers within these 2 groups are not reordered with their parent.

Reordering should work according to the rules specified in the documentation: https://www.telerik.com/blazor-ui/documentation/components/grid/columns/multi-column-headers#reordering

Hello,

 there is inconsistency/behaviour/order in events of the Grid: OnStateInit and OnRead. Which leads to scenario with no clear sollution and would be nice to fix it, and how to solve it as "hotfix".
Also i think its not new in 12.x. release, it exists longer ;)

<TelerikGrid TItem="GData" @ref="gHL" OnRead=@GReadItems OnStateInit="@OnStateGHL">
...
<GridAggregates>
@if(1==2){...}
</GridAggregates>
@code{
protected async Task GReadItems(GridReadEventArgs args)
{
	**hack for C)
	if(gHL==null)return;//state init AVOID 2x call gread PRIOR OnStateInit
...// must be called:
args.AggregateResults = rr.ToDataSourceResult(args.Request).AggregateResults;
...
}
void OnStateGHL(GridStateEventArgs<GData> args) //or async Task doesnt matter
{
//default SORTing:args.GridState = new GridState<GData>
	{
		SortDescriptors = new List<Telerik.DataSource.SortDescriptor>
	{
		new Telerik.DataSource.SortDescriptor{ Member = nameof(GData.DatPorizeni), SortDirection = Telerik.DataSource.ListSortDirection.Descending },
		//new Telerik.DataSource.SortDescriptor{ Member = nameof(GData.Skupina), SortDirection = Telerik.DataSource.ListSortDirection.Ascending }

	}
	};
}
}
	

Problematic scenarios, single page, same grid:

A) when NO aggregates markup EXISTS at all
1. OnStateInit
2. OnRead  - gHL IS NULL
=OK

B) when EMPTY aggregates markup EXISTS
1. OnRead
2. OnStateInit
=FAIL
HOW to read and ui data with correct STATE?
https://www.telerik.com/blazor-ui/documentation/components/grid/state

cannot call gHL.rebind, also gHL is null
NONE initinal "sorting,filtering etc" is set, WRONG data,columns,displayed to the user


C) when SOME real aggregates markup EXISTS
1. OnRead
2. OnStateInit
3. OnRead
=partial FAIL("**hack used"), but managed by if(gHL==null)return


D) "hotfix" used with  GridAggregates="@( HasAggregates ? GridAggregatesTemplate : null )"
act as A or C, but gHL is always null, which is also bad againts C)

Expected:
ALWAYS only A) - First 1.OnStateInit THEN 2.OnRead. its the best one, without any additional hacks = UNIFY the event orders and behaviour.
OR
A) or C)
everything else is unmanagable.
 Especially when initial sorting "is must" and aggregates,columns and so on, are managed by user(non static)
B) is completly WRONG: incorrect event order of OnStateInit and OnRead
D) is againts C) (cannot detect reference of gHL)

related to:
https://feedback.telerik.com/blazor/1654029-onstateinit-does-not-fire-if-gridaggregates-exists-but-is-empty

https://www.telerik.com/forums/grid-onstateinit-event-and-onread-event-chaos

OR how to solve it generally = what is the way to LOAD gridState, and after that, LOAD Data by defined GridState?

Thanks

Description

When going fast over the Grid rows with the mouse cursor, the rows are highlighted after a delay. The delay is more noticeable on higher resolutions (2560x1440 or higher).

Steps To Reproduce

1. Hover the first Grid row and move the mouse cursor towards the last row (or vice versa).

Actual Behavior

In the app that targets .NET10 the row hover styles are applied with a delay, whereas in the app that targets .NET8 the hover styles are applied as soon as the mouse enters the boundaries of a row.

Expected Behavior

Similar performance in applying hover-related styles.

Browser

All

Last working version of Telerik UI for Blazor (if regression)

No response

When you type something in the grid searchbox, there will be a X at the end to clear the box.

However, if you restore the grid from previously stored state like localstorage, and if the box has value, the X is not there.

Thanks!