I am getting the following error with them *only* when loading my site on an iPhone, after the page had been previously loaded on a PC.

2020-11-02T16:19:51.547Z] Error: Microsoft.JSInterop.JSException: An exception occurred executing JS interop: The JSON value could not be converted to System.Double. Path: $ | LineNumber: 0 | BytePositionInLine: 4.. See InnerException for more details.
 ---> System.Text.Json.JsonException: The JSON value could not be converted to System.Double. Path: $ | LineNumber: 0 | BytePositionInLine: 4.
 ---> System.InvalidOperationException: Cannot get the value of a token type 'Null' as a number.
   at System.Text.Json.Utf8JsonReader.TryGetDouble(Double& value)
   at System.Text.Json.Utf8JsonReader.GetDouble()
   at System.Text.Json.Serialization.Converters.JsonConverterDouble.Read(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options)
   at System.Text.Json.JsonPropertyInfoNotNullable`4.OnRead(ReadStack& state, Utf8JsonReader& reader)
   at System.Text.Json.JsonSerializer.HandleNull(Utf8JsonReader& reader, ReadStack& state)
   at System.Text.Json.JsonSerializer.ReadCore(JsonSerializerOptions options, Utf8JsonReader& reader, ReadStack& readStack)
   --- End of inner exception stack trace ---
   at System.Text.Json.ThrowHelper.ReThrowWithPath(ReadStack& readStack, Utf8JsonReader& reader, Exception ex)
   at System.Text.Json.JsonSerializer.ReadCore(JsonSerializerOptions options, Utf8JsonReader& reader, ReadStack& readStack)
   at System.Text.Json.JsonSerializer.ReadValueCore(JsonSerializerOptions options, Utf8JsonReader& reader, ReadStack& readStack)
   at System.Text.Json.JsonSerializer.ReadValueCore(Utf8JsonReader& reader, Type returnType, JsonSerializerOptions options)
   at System.Text.Json.JsonSerializer.Deserialize(Utf8JsonReader& reader, Type returnType, JsonSerializerOptions options)
   at Microsoft.JSInterop.JSRuntime.EndInvokeJS(Int64 taskId, Boolean succeeded, Utf8JsonReader& jsonReader)
   --- End of inner exception stack trace ---
   at Microsoft.JSInterop.JSRuntime.InvokeWithDefaultCancellation[T](String identifier, Object[] args)
   at Telerik.Blazor.Components.TelerikTooltip.OnAfterRenderAsync(Boolean firstRender)

Use any demo and rapidly hover between parent menu items:

I need to make a tooltip more accessible.

---

ADMIN EDIT

The first thing you can do is use the aria-describedby on the tooltip targets and use its value in the tooltip Id parameter to help screen readers. It is up to the screen reader to detect the change in the DOM and read out the new content.

This item is to add attributes to the tooltip such as role="tooltip", aria-live="polite", role="presentation", aria-hidden="false". The exact attributes will depend on more detailed research and may differ from what I have listed here.

---

If I click accidentally click on one of the alignment options, I cannot then unselect it.

===========

ADMIN EDIT

Video of the current behavior attached.

===========

Hi Telerik team,

When I want to bind the Blazor Grid to an ExpandoObject I need to assign the FieldType. I know I have to use non-nullable types.

But I want to use nullable types (for example int?) to have a blank cell within the Grid when there is no value for it. With "typeof(int)" instead of "typeof(int?)" every empty cell shows "0" which I don't want.

Is there any chance to let FieldType accept nullable types?

Best regards,

Rayko

The Custom Filter Menu in the Grid is not working as I would expect.

I am trying to do two things

1. Apply filters programmatically through the Grid State
2. Populate a custom Filter Menu with values that exist in that column

I am doing something very similar to the demo for the custom filter menu: https://demos.telerik.com/blazor-ui/grid/custom-filter-menu

I have observed that if I set a filter programatically through the grid state, those filters are applied to the grid but are not being passed through the FilterMenuTemplateContext object in the FilterMenuTemplate when I open the Filter Menu for that column.  Therefore, I cannot update my custom filter to show which values are currently being filtered on.

Is it by design that the FilterMenuTemplateContext does not contain Filters applied through the grid state or a bug?

---

ADMIN EDIT

As of Dec 2020, there is one outstanding issue - using complex filters (having a CompositeFilterDescriptor) for the FilterRow filter template gets saved in the grid state, but is not loaded as expected - the filter row uses a "regular" FilterDescriptor and cuts off additional descriptors. Thus, the context of the template does not provide all the data from the grid state and you need to extract it manually. I have attached a sample that shows one way of doing that in the StateInit handler.

The FilterMenu already provides all the data in its context and you can bind inputs in the template directly to the filter descriptors. Once the filter row can work with more complex filter descriptors as well, you would be able to create the extra descriptors (if they are not already there) and directly bind the inputs to their value, as opposed to the current approach where view-model fields are used.

---

My users use Tab to focus the masked textbox and when they start typing (its content was highlighted because of getting focus with Tab), that typing action does not put the range (caret) in the correct place - it remains at position 0 rather than going to position 1.

For example, in the below phone mask they type "9" and then "0" and I would expect to get "90" but I get "0".

---

ADMIN EDIT

A workaround is to collapse the range when the input gets focus:

@inject IJSRuntime JsInterop

<input />
<span @onfocusin="@CollapseInputSelection" @ref="@ParentElem">
    <TelerikMaskedTextBox Mask="+1 (000) 000-0000"
                          IncludeLiterals="true"
                          @bind-Value="@CellPhoneNumber"
                          Class="form-control" />
</span>

@* move this script to an actual script file instead of using this hack *@
<script suppress-error="BL9992">
    function collapseInputSelection(root) {
        setTimeout(function () {
            var input = root.querySelector("input");
            if (input) {
                input.setSelectionRange(0, 0);
            }
        }, 20);
    }
</script>

@code{
    string CellPhoneNumber { get; set; }

    ElementReference ParentElem { get; set; }
    async Task CollapseInputSelection()
    {
        await JsInterop.InvokeVoidAsync("collapseInputSelection", ParentElem);
    }
}

---

When using row virtualization, the visible rows are miscalculated when the browser zoom is used (hold control with mouse scroll). 

The result of the miscalculation is that the first row at some point is not visible.

To reproduce the problem you should scroll to the top of the grid and see the first row.

Then start to zoom down and see how the first row is displaced.

Seems like only 50%, 100%, 150%, 200% (multiply of 50%) are calculated correctly in row virtualization

<AdminEdit>

You can reproduce the bug with the attached code.

It's browser-specific and is appearing only in chromium browsers.

It could be related to the way browsers calculate the size of the elements when zooming.

Currently, there is an open bug in the chromium: https://bugs.chromium.org/p/chromium/issues/detail?id=1048147&q=component%3AUI%3EBrowser%3EZoom%20height&can=2 

</AdminEdit>

Hi,

I am using a Blazor TelerikGrid component with Virtual ScrollMode.  I have set a fixed Height, PageSize that exceeds the rows that fit in the grid, and a RowHeight which I have confirmed fits the row contents and resolves to a computed Height of the same value (using Chrome Dev Tools -> Computed tab).  Everything works fine except that sometimes scrolling does not trigger the OnRead event and the rows displayed after scrolling are placeholders. 

I don't experience this problem when I click the scroll arrow buttons (up or down).  I don't experience the problem at all if I drag the scroll bar up or down.  But if I page up/down, or click on the scroll page area up/down it will sometimes work and sometimes not.  If placeholders are shown, I only need to click a scroll button up/down a few times for it to then read and display the correct rows.

To reproduce use the attached VS2019 project, click "Telerik Scroll Issue" nav menu, and in the TelerikGrid click the page down areas of the vertical scrollbar 3 times.

When you move the mouse over the grid cells in this example, several tooltips can remain shown, especially if you move the mouse down so it goes through a tooltip when going towards the next row, and you move it quickly.

<div class="row">
    <TelerikGrid Data="@Items">
        <RowTemplate Context="sampleData">
            @{
                string detailLink = $"info/{sampleData.Id}";
                string className = $"screenshot-hover-{sampleData.Id}";
                string selector = $".{className}";
                <td title="@sampleData.Name" data-id="@sampleData.Id" class="@className">
                    <NavLink href="@detailLink">@sampleData.Name</NavLink>
                </td>
                <td title="@sampleData.Name" data-id="@sampleData.Id" class="@className">
                    <NavLink href="@detailLink">@sampleData.Name</NavLink>
                </td>
                <td title="@sampleData.Name" data-id="@sampleData.Id" class="@className">
                    <NavLink href="@detailLink">@sampleData.Name</NavLink>
                </td>
                <TelerikTooltip TargetSelector="@selector" ShowOn="@TooltipShowEvent.Hover" Position="@TooltipPosition.Bottom">
                    <Template Context="ttipContext">
                        @{
                            var dataAttributes = ttipContext.DataAttributes;
                            var title = ttipContext.Title;
                            if (title != null && dataAttributes.ContainsKey("id"))
                            {
                                <img src="images/@(dataAttributes["id"])" alt="@title" />
                                <p>@title</p>
                            }
                        }
                    </Template>
                </TelerikTooltip>
            }
        </RowTemplate>

        <GridColumns>
            <GridColumn Field="@(nameof(SampleData.Name))" />
            <GridColumn Field="@(nameof(SampleData.Address))" />
            <GridColumn Field="@(nameof(SampleData.PhoneNumber))" />
        </GridColumns>
    </TelerikGrid>
</div>

@code {
    class SampleData
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Address { get; set; }
        public string PhoneNumber { get; set; }
    }

    SampleData[] Items { get; set; }

    protected async override Task OnInitializedAsync()
    {
        const int sampleSize = 25;
        Items = new SampleData[sampleSize];
        for (int i = 0; i < sampleSize; i++)
        {
            Items[i] = new SampleData
            {
                Id = i,
                Name = $"{i}.SomeName",
                Address = $"{i}{i}{i}{i} Cherry Lane",
                PhoneNumber = $"1-512-{i % 100:00}4-6000",
            };

        }

        await Task.CompletedTask;
    }
}

Hi,

This is easily viewable in your demos.  Using Safari, go to:

https://demos.telerik.com/blazor-ui/dateinput/overview

Try to use keyboard arrows left and right and up/down to change date.  It doesn't hold the selected date part.  

Works fine in Chrome / Firefox.

By the following steps, the problem occurs:

1. Click on line number 1 to focus the row
2. Press the Down-Key 19 times to navigate to line 20
3. Try to navigate to line 21 via the Down-Key
4. -> No navigation possible via keyboard to the lines below
5. Try to navigate backwards via Up-Key to line 1
6. -> Navigation stops at line 15

So, it not possible to navigate through the whole grid with virtualized rows when Navigable=true





@* Scroll the grid instead of paging *@

<TelerikGrid Data=@GridData
             ScrollMode="@GridScrollMode.Virtual" Navigable="true"
             Height="480px" RowHeight="60" PageSize="20"
             Sortable="true" FilterMode="@GridFilterMode.FilterMenu">
    <GridColumns>
        <GridColumn Field="Id" />
        <GridColumn Field="Name" Title="First Name" />
        <GridColumn Field="LastName" Title="Last Name" />
        <GridColumn Field="HireData" Width="200px">
            <Template>
                @((context as SampleData).HireDate.ToString("MMMM dd, yyyy"))
            </Template>
        </GridColumn>
    </GridColumns>
</TelerikGrid>

@code {
    public List<SampleData> GridData { get; set; }

    protected override async Task OnInitializedAsync()
    {
        GridData = await GetData();
    }

    private async Task<List<SampleData>> GetData()
    {
        return Enumerable.Range(1, 1000).Select(x => new SampleData
        {
            Id = x,
            Name = $"name {x}",
            LastName = $"Surname {x}",
            HireDate = DateTime.Now.Date.AddDays(-x)
        }).ToList();
    }

    public class SampleData
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string LastName { get; set; }
        public DateTime HireDate { get; set; }
    }
}

Create the WebAssembly CRUD example from the New Project Wizard and go to the Form page.

Type a year in the date picker. Do not remove the focus and type another year. After doing this a few times the input visibly lags and the form becomes slow.

---

ADMIN EDIT

A potential workaround could be to disable the pointer events so that the users will have a harder time focusing the input so they are more likely to use the drodown to choose dates:

   .k-datepicker .k-dateinput input {
        pointer-events: none;
    }

<TelerikDatePicker Value="@person.StartDate"
                   OnChange="@( (object dt) => person.StartDate = (DateTime)dt )"
                   ValueExpression="@( () => person.StartDate )"
                   Width="100%" Id="StartDateDP">
</TelerikDatePicker>

---

In a Grid loaded with data made of ExpandoObject, set an aggregate GridAggregateType.Sum breaks the grouping feature while GridAggregateType Max, Min and Count work properly

Please find the attached project: in the grid on Index.razor grouping does not work, just comment Index.razor:43 to restore grouping feature

Exception message:

Error: System.InvalidOperationException: No generic method 'Sum' on type 'System.Linq.Enumerable' is compatible with the supplied type arguments and arguments. No type arguments should be provided if the method is non-generic. 
   at System.Linq.Expressions.Expression.FindMethod(Type type, String methodName, Type[] typeArgs, Expression[] args, BindingFlags flags)
   at System.Linq.Expressions.Expression.Call(Type type, String methodName, Type[] typeArguments, Expression[] arguments)
   at Telerik.DataSource.Expressions.EnumerableSelectorAggregateFunctionExpressionBuilder.CreateMethodCallExpression(LambdaExpression memberSelectorExpression)
   at Telerik.DataSource.Expressions.EnumerableSelectorAggregateFunctionExpressionBuilder.CreateAggregateExpression()
   at Telerik.DataSource.EnumerableSelectorAggregateFunction.CreateAggregateExpression(Expression enumerableExpression, Boolean liftMemberAccessToNull)
   at Telerik.DataSource.Expressions.GroupDescriptorExpressionBuilder.<ProjectionPropertyValueExpressions>b__39_0(AggregateFunction f)
   at System.Linq.Enumerable.SelectIListIterator`2.ToList()
   at Telerik.DataSource.Expressions.GroupDescriptorExpressionBuilder.CreateProjectionInitExpression()
   at Telerik.DataSource.Expressions.GroupDescriptorExpressionBuilder.CreateAggregateFunctionsProjectionMemberBinding()
   at Telerik.DataSource.Expressions.QueryableAggregatesExpressionBuilder.CreateMemberBindings()+MoveNext()
   at System.Collections.Generic.LargeArrayBuilder`1.AddRange(IEnumerable`1 items)
   at System.Collections.Generic.EnumerableHelpers.ToArray[T](IEnumerable`1 source)
   at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
   at System.Dynamic.Utils.CollectionExtensions.ToReadOnly[T](IEnumerable`1 enumerable)
   at System.Linq.Expressions.Expression.MemberInit(NewExpression newExpression, IEnumerable`1 bindings)
   at Telerik.DataSource.Expressions.GroupDescriptorExpressionBuilder.CreateSelectBodyExpression()
   at Telerik.DataSource.Expressions.GroupDescriptorExpressionBuilder.CreateSelectExpression()
   at Telerik.DataSource.Expressions.GroupDescriptorExpressionBuilderBase.CreateQuery()
   at Telerik.DataSource.Extensions.QueryableExtensions.Aggregate(IQueryable source, IEnumerable`1 aggregateFunctions)
   at Telerik.DataSource.Extensions.QueryableExtensions.CreateDataSourceResult[TModel,TResult](IQueryable queryable, DataSourceRequest request, Func`2 selector)
   at Telerik.DataSource.Extensions.QueryableExtensions.ToDataSourceResult(IQueryable queryable, DataSourceRequest request)
   at Telerik.DataSource.Extensions.QueryableExtensions.ToDataSourceResult(IEnumerable enumerable, DataSourceRequest request)
   at Telerik.Blazor.Data.TelerikDataSourceBase.ProcessData(IEnumerable data)
   at Telerik.Blazor.Components.Common.DataBoundComponent`1.ProcessDataInternal()
   at Telerik.Blazor.Components.Common.DataBoundComponent`1.ProcessDataAsync()
   at Telerik.Blazor.Components.TelerikGrid`1.DataBoundProcessData()
   at Telerik.Blazor.Components.TelerikGrid`1.ProcessDataAsync()
   at Telerik.Blazor.Components.TelerikGrid`1.ApplyFiltersAsync()
   at Telerik.Blazor.Components.TelerikGrid`1.OnFilterChange(FilterDescriptorBase filter)
   at Telerik.Blazor.Components.Common.Filters.TelerikFilterHeader`1.Filter(FilterDescriptor filterDescriptor)
   at Telerik.Blazor.Components.Common.Filters.TelerikFilterHeader`1.OnValueChanged(Object newValue)
   at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__139_0(Object state)
   at Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContext.ExecuteSynchronously(TaskCompletionSource`1 completion, SendOrPostCallback d, Object state)
   at Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContext.<>c.<.cctor>b__23_0(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location where exception was thrown ---
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContext.ExecuteBackground(WorkItem item)

I am passing an HTML table, which, on some elements, has a style attribute. When it renders the style attribute is missing which breaks the layout.

Passed HTML:

<table>
    <tr>
         <td style="width:100px;background-color:#FF0000;">Test</td> 
   </tr>
</table>

Rendered HTML from the Editor (missing style attribute):

<table class="k-table"><tbody><tr><td><p>Test</p></td></tr></tbody></table>

I am using EF on my backend and when I group I get an error like this one:

Unhandled exception rendering component: Processing of the LINQ expression '(GroupByShaperExpression:
      KeySelector: (t.FirstName), 
      ElementSelector:(EntityShaperExpression: 
          EntityType: Customer
          ValueBufferExpression: 
              (ProjectionBindingExpression: EmptyProjectionMember)
          IsNullable: False
      )
      )' by 'RelationalProjectionBindingExpressionVisitor' failed. This may indicate either a bug or a limitation in EF Core. See https://go.microsoft.com/fwlink/?linkid=2101433 for more detailed information.
System.InvalidOperationException: Processing of the LINQ expression '(GroupByShaperExpression:
KeySelector: (t.FirstName), 
ElementSelector:(EntityShaperExpression: 
    EntityType: Customer
    ValueBufferExpression: 
        (ProjectionBindingExpression: EmptyProjectionMember)
    IsNullable: False
)
)' by 'RelationalProjectionBindingExpressionVisitor' failed. This may indicate either a bug or a limitation in EF Core. See https://go.microsoft.com/fwlink/?linkid=2101433 for more detailed information.
   at Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.VisitExtension(Expression extensionExpression)
   at System.Linq.Expressions.Expression.Accept(ExpressionVisitor visitor)

and a lot more line through the EF Core expression classes.

-----

ADMIN EDIT

    protected override void OnInitialized()
    {
        GridData = ProductService.GetProducts().ToList();
    }

----

The TimePicker scroll wheels are janky and difficult to use on mobile.  They tend to jump around while scrolling with touch input.

Is this on the roadmap for improvement?  We are working on a project and need to decide whether to roll our own TimePicker in the meantime.

(Note: this is an issue on both client/server side, but I am forced to choose one.)