App just crashed with the below exception.  My code isn't in the stack trace. Chances are there is no proper validation on parameters, allowing me to supply bad data, which later causes this problem.  Please validate the data better, debugging these things is not easy.

Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware: Error: An unhandled exception has occurred while executing the request.

System.ArgumentNullException: Value cannot be null. (Parameter 'source')
   at System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at Telerik.Blazor.Components.TelerikGrid`1.SetProcessedData(IEnumerable data)
   at Telerik.Blazor.Components.Common.DataBoundComponent`1.ProcessDataSourceResult(DataSourceResult result)
   at Telerik.Blazor.Components.Common.GridBase`1.ProcessDataSourceResult(DataSourceResult result)
   at Telerik.Blazor.Components.Common.DataBoundComponent`1.ProcessDataInternal()
   at Telerik.Blazor.Components.TelerikGrid`1.ProcessDataInternal()
   at Telerik.Blazor.Components.Common.DataBoundComponent`1.OnParametersSetAsync()
   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.Rendering.ComponentState.SetDirectParameters(ParameterView parameters)
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InitializeNewComponentFrame(DiffContext& diffContext, Int32 frameIndex)
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InitializeNewSubtree(DiffContext& diffContext, Int32 frameIndex)
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InsertNewFrame(DiffContext& diffContext, Int32 newFrameIndex)
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForRange(DiffContext& diffContext, Int32 oldStartIndex, Int32 oldEndIndexExcl, Int32 newStartIndex, Int32 newEndIndexExcl)
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.ComputeDiff(Renderer renderer, RenderBatchBuilder batchBuilder, Int32 componentId, ArrayRange`1 oldTree, ArrayRange`1 newTree)
   at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, Exception& renderFragmentException)
   at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()
   at Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToRenderQueue(Int32 componentId, RenderFragment renderFragment)
   at Microsoft.AspNetCore.Components.ComponentBase.StateHasChanged()
   at Microsoft.AspNetCore.Components.ComponentBase.CallOnParametersSetAsync()
   at Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()
   at Microsoft.AspNetCore.Components.Rendering.ComponentState.SetDirectParameters(ParameterView parameters)
   at Microsoft.AspNetCore.Components.RenderTree.Renderer.RenderRootComponentAsync(Int32 componentId, ParameterView initialParameters)
   at Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.RenderComponentAsync(Type componentType, ParameterView initialParameters)
   at Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContext.<>c__11`1.<<InvokeAsync>b__11_0>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.ViewFeatures.StaticComponentRenderer.PrerenderComponentAsync(ParameterView parameters, HttpContext httpContext, Type componentType)
   at Microsoft.AspNetCore.Mvc.ViewFeatures.ComponentRenderer.PrerenderedServerComponentAsync(HttpContext context, ServerComponentInvocationSequence invocationId, Type type, ParameterView parametersCollection)
   at Microsoft.AspNetCore.Mvc.ViewFeatures.ComponentRenderer.RenderComponentAsync(ViewContext viewContext, Type componentType, RenderMode renderMode, Object parameters)
   at Microsoft.AspNetCore.Mvc.TagHelpers.ComponentTagHelper.ProcessAsync(TagHelperContext context, TagHelperOutput output)
   at Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner.<RunAsync>g__Awaited|0_0(Task task, TagHelperExecutionContext executionContext, Int32 i, Int32 count)
   at EnrichmentEngine.Pages.Pages__Host.<ExecuteAsync>b__15_1() in C:\Users\PeterDrier\source\repos\fleet\src\sovereign\dotnet\services\studio-calc-engine\SummaReportsPoc\Pages\_Host.cshtml:line 25
   at Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperExecutionContext.SetOutputContentAsync()
   at EnrichmentEngine.Pages.Pages__Host.ExecuteAsync() in C:\Users\PeterDrier\source\repos\fleet\src\sovereign\dotnet\services\studio-calc-engine\SummaReportsPoc\Pages\_Host.cshtml:line 7
   at Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderPageCoreAsync(IRazorPage page, ViewContext context)
   at Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderPageAsync(IRazorPage page, ViewContext context, Boolean invokeViewStarts)
   at Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderAsync(ViewContext context)
   at Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ViewContext viewContext, String contentType, Nullable`1 statusCode)
   at Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ViewContext viewContext, String contentType, Nullable`1 statusCode)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeResultAsync>g__Logged|22_0(ResourceInvoker invoker, IActionResult result)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResultFilterAsync>g__Awaited|30_0[TFilter,TFilterAsync](ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResultExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext[TFilter,TFilterAsync](State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeResultFilters()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|25_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddlewareImpl.<Invoke>g__Awaited|8_0(ExceptionHandlerMiddlewareImpl middleware, HttpContext context, Task task)

I have a Grid with TItem="Dictionary<string, object>". I am not able to programmatically set EditItem and EditField through state.

I tried saving the state while editing to ensure the EditItem and EditField will be properly stored. When I try to retrieve this state object afterwards nothing happens.

Reproduction: https://blazorrepl.telerik.com/GnvYaIbd19iOZ6GH08.

Currently, if I call Grid.AutoFitAllColumnsAsync "too early" it throws a null reference exception.

I am aware that this is a limitation but the behavior can be improved. For example, handle the exception and provide some useful information or give me a programmatic way to know if it's too early to call autofit.

The Grid PageSizes DropDownList will not select a new value if it the current value is not visible in the open dropdown. This can happen if there are too many items in the DropDownList and the user has scrolled the PageSizes dropdown.

The problem occurs only when Navigable="true".

Here is a REPL test page

The easiest workaround is to fewer items in the PageSizes DropDownList, so that there is no need for scrolling.

I am using Telerik Grid in our project and I have enabled the feature Reorderable="true". At GridColumnMenuSettings I am getting the following options:

Set column position :

• Move Next 
• Move Previous

Those options are commonly showing for all columns but I want to disable "Move Next" option for the last column and "Move Previous" option for the first column as these options are not applicable to the corresponding columns.

I noticed a different behavior when filtering programmatically through the state and when you use the filter UI.

When filtering programmatically the filter is set after the data arrives. I am using a FiltterMenu and the filter icon is colored to indicate there is an applied filter only after the data is filtered. When filtering from the menu, I can the opposite behavior - the filter is set first and then the data is filtered. To me, this seems to be the correct behavior.

Reproduction: https://blazorrepl.telerik.com/wSavwTPd367WqA9r37.

I have a TelerikGrid with Reordarable enabled inside of a TelerikWindow. Reordering of the column works fine only the drop clue is not showing. I think this is because the z-index is incorrect.

Missing drop clue:

z-index of drop clue is 10000:

z-index of window is 10002:

We want frozen columns exactly like this:

• https://demos.telerik.com/aspnet-core/grid/frozen-columns

• https://www.telerik.com/kendo-angular-ui/components/grid/columns/locked/#toc-setup

When a user deletes a record that decreases the number of pages on that Grid, and then they try to edit or add a record, they get stuck in the OnCancel event handler, which gets called over and over in an endless loop.

The behavior can be seen:

• After deleting a record in the Grid, which decreases the number of pages.
• The Grid is using a confirmation dialog from the DialogFactory for the Cancel action.

Steps To Reproduce

https://blazorrepl.telerik.com/GokIvFva42BLx7yl37

1. Delete item 11. The Grid will move you to page 1.
2. Try to edit or add a new item. OnCancel will fire in a loop.
3. If OnAdd and OnEdit are not defined, the loop will occur in OnUpdate and OnCancel.

On grids with a lot of data there is a delay between when the grid is assigned the data to when the grid shows the data.  During this UI painting period, the NoDataTemplate is displayed for a second or two.

The grid should not show the NoDataTemplate unless the data source is loaded with an empty collection, not just while it is still trying to show the data.

Note: Having a generic message like in the documentation "No Data available / The data is still loading ..." is not satisfying our users. (Blazor Grid - No Data Template - Telerik UI for Blazor) These should really be two different states that can show different messages.

Thanks

When the user drags a third column to the Grid Group Panel, it ends up being second, instead of last. It looks like each new column is inserted at index 1, instead of appended last (when this is the user's intent).

@using Telerik.DataSource

<p>Group by a third column, so that it should come last in the Group Panel:</p>

<TelerikGrid @ref="@GridRef"
             Data="@GridData"
             Pageable="true"
             Sortable="true"
             Groupable="true"
             FilterMode="GridFilterMode.FilterRow"
             OnStateInit="@( (GridStateEventArgs<Employee> args) => OnGridStateInit(args) )"
             OnStateChanged="@( (GridStateEventArgs<Employee> args) => OnGridStateChanged(args) )">
    <GridColumns>
        <GridColumn Field="@nameof(Employee.Name)" />
        <GridColumn Field="@nameof(Employee.Team)" />
        <GridColumn Field="@nameof(Employee.Salary)" />
        <GridColumn Field="@nameof(Employee.OnVacation)" />
    </GridColumns>
</TelerikGrid>

@code {
    private TelerikGrid<Employee>? GridRef { get; set; }

    private List<Employee> GridData { get; set; } = new();

    private void OnGridStateInit(GridStateEventArgs<Employee> args)
    {
        args.GridState.GroupDescriptors = new List<GroupDescriptor>();

        args.GridState.GroupDescriptors.Add(new GroupDescriptor()
        {
            Member = nameof(Employee.Team),
            MemberType = typeof(string)
        });

        args.GridState.GroupDescriptors.Add(new GroupDescriptor()
        {
            Member = nameof(Employee.OnVacation),
            MemberType = typeof(bool)
        });
    }

    private async Task OnGridStateChanged(GridStateEventArgs<Employee> args)
    {
        if (args.PropertyName == "GroupDescriptors" && args.GridState.GroupDescriptors.Count > 2 && GridRef != null)
        {
            var secondGroupDescriptor = args.GridState.GroupDescriptors.ElementAt(1);

            args.GridState.GroupDescriptors.Remove(secondGroupDescriptor);
            args.GridState.GroupDescriptors.Add(secondGroupDescriptor);

            await GridRef.SetStateAsync(args.GridState);
        }
    }

    protected override void OnInitialized()
    {
        var rnd = new Random();

        for (int i = 1; i <= 20; i++)
        {
            GridData.Add(new Employee()
            {
                Id = i,
                Name = "Name " + i,
                Team = "Team " + (i % 4 + 1),
                Salary = (decimal)rnd.Next(1000, 3000),
                OnVacation = i % 3 == 0
            });
        }
    }

    public class Employee
    {
        public int Id { get; set; }
        public string Name { get; set; } = string.Empty;
        public string Team { get; set; } = string.Empty;
        public decimal Salary { get; set; }
        public bool OnVacation { get; set; }
    }
}

The Grid exits edit mode when expanding or collapsing rows in a hierarchy scenario. This only happens when OnStateChanged is set.

Test page that reproduces the behavior: https://blazorrepl.telerik.com/wIkJvdlo09hXCV8u03

Could there be an option to NOT close the filter dropdown when the clear button is pressed? Is there an AutoClose parameter or something else?

The Grid will cancel the insertion of a new item when:

• the new item is not saved yet
• the new item is expanded and its DetailTemplate is visible
• the user changes the value of a column that has an editor template

Blazor REPL test page

===

In the meantime, a possible workaround is to hide the expand button for items, which are not added to the "permanent" Grid data yet. Here is how to do it with CSS:

.k-grid-add-row .k-hierarchy-cell .k-icon {
    display: none;
}