I've followed everything i can find about enforcing UTF-8 encoding, but this is still happening. It only happens in the drop down options of the aforementioned components, not after they are selected and not in the ASP.NET core <InputSelect> component.


Hi there
I'm trying to use DropDownlist with the Grouping field and the OnReadEvent, with mode = DropDownScrollMode.Scrollable
The OnRead event provides the grouping field to the request. The request is sent to my (API) server that handles the request, and the result is returned . Then after my OnReadHandler method ands, I get an internal exception: "System.NullReferenceException: 'Object reference not set to an instance of an object.'"
with following stack:
Telerik.Blazor.dll!Telerik.Blazor.Components.Common.TelerikSelectBase<SNG.LccNion.API.Model.Dto.IDDescriptiveDto, string>.ProcessGroupData(System.Collections.IEnumerable data) Unknown
Telerik.Blazor.dll!Telerik.Blazor.Components.Common.TelerikSelectBase<SNG.LccNion.API.Model.Dto.IDDescriptiveDto, string>.SetProcessedData(System.Collections.IEnumerable data) Unknown
Telerik.Blazor.dll!Telerik.Blazor.Components.TelerikDropDownList<SNG.LccNion.API.Model.Dto.IDDescriptiveDto, string>.SetProcessedData(System.Collections.IEnumerable data) Unknown
Telerik.Blazor.dll!Telerik.Blazor.Components.Common.DataBoundComponent<SNG.LccNion.API.Model.Dto.IDDescriptiveDto>.ProcessOnReadResult(Telerik.Blazor.Components.ReadEventArgs args) Unknown
Telerik.Blazor.dll!Telerik.Blazor.Components.Common.TelerikSelectBase<SNG.LccNion.API.Model.Dto.IDDescriptiveDto, string>.ProcessOnReadResult(Telerik.Blazor.Components.ReadEventArgs args) Unknown
Telerik.Blazor.dll!Telerik.Blazor.Components.Common.DataBoundComponent<SNG.LccNion.API.Model.Dto.IDDescriptiveDto>.ProcessOnReadData() Unknown
[Resuming Async Method]
> System.Private.CoreLib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<System.Threading.Tasks.VoidTaskResult>.AsyncStateMachineBox<Telerik.Blazor.Components.Common.DataBoundComponent<SNG.LccNion.API.Model.Dto.IDDescriptiveDto>.<ProcessOnReadData>d__39>.ExecutionContextCallback(object s) Line 292 C#
System.Private.CoreLib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) Line 179 C#
System.Private.CoreLib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<System.Threading.Tasks.VoidTaskResult>.AsyncStateMachineBox<Telerik.Blazor.Components.Common.DataBoundComponent<SNG.LccNion.API.Model.Dto.IDDescriptiveDto>.<ProcessOnReadData>d__39>.MoveNext(System.Threading.Thread threadPoolThread) Line 372 C#
System.Private.CoreLib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<System.Threading.Tasks.VoidTaskResult>.AsyncStateMachineBox<Telerik.Blazor.Components.Common.DataBoundComponent<System.__Canon>.<ProcessOnReadData>d__39>.MoveNext() Line 350 C#
System.Private.CoreLib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod__12_0(System.Action innerContinuation, System.Threading.Tasks.Task innerTask) Line 281 C#
System.Private.CoreLib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunCallback(System.Threading.ContextCallback callback, object state, ref System.Threading.Tasks.Task currentTask) Line 697 C#
System.Private.CoreLib.dll!System.Threading.Tasks.Task.RunContinuations(object continuationObject) Line 3486 C#
System.Private.CoreLib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<Telerik.Blazor.Components.ReadEventArgs>.SetResult(Telerik.Blazor.Components.ReadEventArgs result) Line 478 C#
[Completed] Telerik.Blazor.dll!Telerik.Blazor.Components.TelerikDropDownList<SNG.LccNion.API.Model.Dto.IDDescriptiveDto, string>.TriggerReadAsync(Telerik.DataSource.DataSourceRequest request) Unknown
I am struggling to handle the request correctly and provide an answer back to the list that it can handle properly.
Nevertheless I get errors. Is there a working example of using the OnRead event with the GroupField property set to a property of the TItem? Or is this combination impossible inspite of DropDownScrollMode.Scrollable mode?
BTW - In case of large dropdownlist result set I want to fall back to virtual mode, and drop the grouping option, as it is documented that these are not compatible. (This is handled blazor side by checking the dataset count before the first OnRead call)

I've tried to find documentation on how to modify the CSS for the dropdownlist and it's popup but can't seem to figure out how to change the "Search" area size, nor the "Select Type" (they are too large).
I was able to figure out how to adjust the actual items:
.custom-compact-dropdownlist-popup .k-list-item {
padding-top: 2px;
padding-bottom: 2px;
font-size: 0.90em;
}
and reference:
<DropDownListSettings>
<DropDownListPopupSettings Class="custom-compact-dropdownlist-popup" />but I don't know what to use in CSS ... is there a list somewhere of the ".k" class selectors?
Rob.

I have this javascript exception when use MultiColumnComboBox (but sometime also with ComboBox / DropDown).
If i continue debugging it go without issue, but it break always on component load.
I'm trying to adjust the existing size definitions as outlined here in your docs:
https://www.telerik.com/blazor-ui/documentation/components/dropdownlist/appearance
I'd like to adjust the definition for sm, md, lg as they don't work well with TailwindCSS settings. For example lg is just a tad too large and md is a tad too small
This is lg:
This md:
I want to match the border size to our standard input text (aka Postal Code example above). I can't seem to find where sm, lg, md are defined? And, is there a relative "simple" way to modify without going down a "custom" theme path?
Rob.


<div class="gsi-background-color-light" style="height: 41px; display:flex;justify-content:space-between;">
<div class="align-self-center gsi-font-kendo gsi-margin-0">
Patient Filters
</div>
<TelerikButton Id="filterChevronButton"
FillMode="Clear"
Class="gsi-border-width-0 gsi-border-color-white gsi-padding-8"
Icon="@( FilterVisible? Telerik.SvgIcons.SvgIcon.Filter : Telerik.SvgIcons.SvgIcon.Filter)"
OnClick="@(() => ExpandCollapse())" />
</div>
<TelerikAnimationContainer @ref="@AnimContainer"
Class="gsi-background-color-light gsi-margin-5 k-rounded-0"
Width="100%"
Height="100vm">
<TelerikStackLayout Spacing="1px" Class="gsi-margin-5">
<TelerikCard Width="25vh">
<CardBody>
<div class="form-group-short">
<label class="col-form-label" for="firstName">First Name</label><br />
<TelerikTextBox @bind-Value="@FirstNameFilter"
Name="firstName"
Placeholder="-No Filter-"
OnChange="@(x => OnFilterChanged(nameof(FirstNameFilter), x))">
</TelerikTextBox>
</div> private async Task OnFilterChanged(string propertyName, object newValue)
{
await GetPatients();
ExpandCollapse(false);
} private async Task OnFilterChanged(string propertyName, object newValue)
{
object existingValue = this.GetPropertyValue(propertyName);
if (newValue != existingValue)
{
this.SetPropertyValue(propertyName, newValue);
await GetPatients();
ExpandCollapse(false);
}
} public async void ExpandCollapse(bool? filterVisible = null)
{
if (filterVisible.HasValue)
{
await AnimContainer.ToggleAsync();
FilterVisible = filterVisible.Value;
}
else
{
await AnimContainer.ToggleAsync();
FilterVisible = !FilterVisible;
}
}The user doesn't have to select anything in my drop down. So, if they select something and change their mind and want to clear it... how do I do it?
<TelerikDropDownList @bind-Value="@SessionOptionIndex1"
Data="@SessionOption1Items"
TextField="Name" ValueField="Id" />