When enabling/disabling a form element that is defined in a child component, the element is successfully disabled, however a console error occurs. The error occurs whether the child component makes the update or the parent makes the update through a passed parameter.  The error does not occur for form elements defined in the parent.  The error does not occur for basic html input elements defined in the child. 

Element definition:

<TelerikTextBox 
     Id="ElementMisc" 
     AutoComplete="new-password" 
     @bind-Value="@_searchModel.ElementMisc" 
     Enabled="!_elementSelectMode" 
     class="textbox-75"
     DebounceDelay="0">
 </TelerikTextBox>

Update Code defined in child:

 if (results.Data.Count > 1)
 {   
     _elementSelectMode= true;
     StateHasChanged();

 }

Console Error:

Uncaught (in promise) Error: Assertion failed - heap is currently locked
    at mr (blazor.web.js:1:158963)
    at Object.beginInvokeDotNetFromJS (blazor.web.js:1:157244)
    at w.invokeDotNetMethodAsync (blazor.web.js:1:3978)
    at C.invokeMethodAsync (blazor.web.js:1:5486)
    at r.invokeMethodAsync (telerik-blazor.js:22:1272553)
    at r.onBlur (telerik-blazor.js:22:1463592)
    at ye.setOrRemoveAttributeOrProperty (blazor.web.js:1:28630)
    at ye.applyAttribute (blazor.web.js:1:27574)
    at ye.applyEdits (blazor.web.js:1:24601)
    at ye.updateComponent (blazor.web.js:1:23606)

I recently had a breakthrough moment in my journey learning and using Telerik Blazor that I believe highlights a crucial area for improvement in your documentation strategy. I believe that this will significantly help me learn and use your components,  I suspect others may still fall into the same trap as me.  I'm confident that implementing this suggestion will make the learning process considerably easier for all users.

As a developer with over 35 years of experience, my initial approach to learning new technologies is to rely heavily on official documentation. I expect to find comprehensive resources that facilitate a smooth learning curve. However, after years of struggling with Telerik Blazor components, I stumbled upon the Component Demos section (https://demos.telerik.com/blazor-ui). This discovery, triggered by a specific Google search for "telerik blazor drawer submenu," is a game-changer.

The Component Demos contain a wealth of practical examples for each component, offering invaluable "cut-and-paste" starting points. Before this, I primarily relied on StackOverflow and other online resources and until today, I finally landed on the Telerik Blazor Component demos. The fact that I have been unaware of this resource for so long represents a significant shortcoming in the current documentation.  How easy it would be to add a link in the overview to the component's demos which would have saved me countless hours of trying to solve problems that have already been solved on the demos page, like the Drawer submenu mentioned above.

   Integrating direct links to each component's respective demo page within the main documentation would dramatically improve the discover-ability of these demos and empower users to independently solve many common challenges. Currently, the limited examples within the documentation are insufficient for comprehensive understanding.

In summary, prominently featuring the Component Demos within the core Telerik Blazor documentation would vastly enhance the learning experience, reduce support requests, and empower developers to utilize the full potential of your components.

Peter

Hi Telerik Support

This is related to the feedback portal item:  The Grid header gets focus only for the first time when tabbing

I had raised the above issue, now I can see that the issue is fixed in 7.0.0. But the fix does not work when the TelerikGrid is inside a TelerikWindow. 

Please find the REPL sample https://blazorrepl.telerik.com/QIvmPrlI39rZ4whP10 

Is there a work around for the scenario where the grid is inside a popup window?

Regards

Bably

We would like the ability to customize the calendar's month header.

For instance, we would like to add a row displaying the month name and year, as shown in the attached screenshot.

Describe the bug

The class 'k-tabstrip' item is missing in the rendering of the TabStrip component.

To Reproduce

1. Go to the following demo and open the DevTools:

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

2. Check the source of truth:

https://github.com/telerik/kendo-themes/blob/develop/tests/tabstrip/tabstrip.html 

Actual results

The class 'k-tabstrip-item' is missing.

Expected behavior

The class 'k-tabstrip-item' to be present.

Additional context

ThemeBuilder generates styles for the items of the TabStrip component with selectors like these:

.k-tabstrip .k-tabstrip-items-wrapper .k-tabstrip-items.k-reset.k-tabstrip-items-start .k-item.k-tabstrip-item.k-active .k-link

This works in other technologies, such as Kendo React, but it doesn't take effect in Blazor applications because of the issue.

Reported through t.1672526.

On a grid grouped by one or more fields, provide an option for end users to expand/collapse all rows at will. The following image is a suggestion of where this option (most likely a button) should appear:

On a grid grouped by a field (using GroupDescriptors) where the amount of records exceed the page limit, therefore generating multiple pages, provide an option to keep the collapsed/expanded states of the groups when navigating through the pages.

In-house we implemented the following approach to mitigate this issue: when calling OnRead event, after processing the data (order, filter, group, etc) we're mapping the groups and subgroups to its corresponding indexes. When page changing, we then store the current state of the groups, alongside its keys (aka  the label of the group). After page changing and mapping the groups and subgroups again, we just match the group names stored in this temporary state with the group names of the new page and restore the state.

For example: start with all groups initially collapsed, page 1 has groupA and groupB and user expanded groupB, changed to page 2, which has the remaining records of groupB and groupC. In this case it will restore groupB as expanded while groupC keeps collapsed.

Example to demonstrate the issue: https://blazorrepl.telerik.com/melmEeFi43owNZBe50

Hi,

Can I request that the Pdf Viewer:

- Load multiple pdf files on open. Maybe via an array of file names.

     - We use a different viewer due to this capability. For Human Resource files you need the ability to load numerous files into one viewer to show a complete
         document. The current one file option doesn't work for us.

- Display thumbnails of the loaded pages.
      - Thumbnail onclick to move to a specific page.

Regards,
Graham O'Riley

Steps to reproduce:

1. Insert a simple TelerikGrid on your page
2. Add Columns with templates for each property
3. Specify a Column Template

See https://blazorrepl.telerik.com/GyPvFMFr00zLEEdG00

Problem / Inconvenience

• Context has to be converted/cast before access to the each property is possible
• Grid columns are not generic which makes them hard to use sometimes
• Fields have to be specified by name (may lead to wrong names after changing)

Solution / Feature Request

• Provide new generic columns (to ensure no current implementations break)
  
• Add [CascadingTypeParameter(nameof(TItem))] to the TelerikGrid
• GridColumns automatically "inherit" the typeparam TItem
  

Idea from: Blazor QuickGrid

Benefits

• GridColumns can be specified with Expression
• Template context does not have to be cast anymore
• Renaming properties affect expression or an error is display (property does not exist)

<GridColumn For="@(t => t.Name)">
        <Template>
                <div>
                    @item.Name
                </div>
        </Template>
</GridColumn>

Hi Team,

I am looking for captcha component to verify user as human like below screenshot. Please let me know if this feature is available

For example, selecting Bootstrap-Main-Dark theme in the Project Wizard does not apply the dark mode.

===ADMIN EDIT===

For the time being, a possible workaround is to manually add class="k-body" to the <body> tag of your application. This will ensure, that the dark mode is correctly applied. This is required because, by design, the Default theme does not enable the typography system. The "k-body" class is required for the typography system to work properly on the document level and apply the predefined typography values to the page. For more detailed information, refer to Design System Documentation.

Good Morning,

I have recently started getting random and repeated Javascript errors when debugging my project using your controls for Blazor.  It is completely random (sometimes happens immediately at project start, sometimes when navigating to a new page, sometimes when interacting with a control).  It is ALWAYS the same error....

TypeError: Cannot read properties of undefined (reading 'visible') 

Message=
  Source=
  StackTrace:
  at __webpack_modules__.8219.constructor.onMouseEnter (https://localhost:44307/_content/Telerik.UI.for.Blazor/js/telerik-blazor.js?v=ITaQSsBTBmdJoUpPr2KiZ7JwhfKjwa7SGa6zvlv9kkU:50:1442661)

I am using the most current version of your product.  I have gone through your "Javascript Errors" page and have worked through all the suggestions.  Nothing resolves it.

This is becoming a giant time sink while trying to work on a project.  What can we do to get appropriate error handling on your end to prevent these issues?

Thanks

I get validation issues for the selection Checkboxes and the PageSizes dropdown as they do not have id or name attributes:

The behavior can be reproduced in the online demo: Blazor Data Grid - Overview

Please expose the current data of the data bound select components when using OnRead. This will spare the need to cache data for the second time in-memory, or make a database request, or search by non-ID value when the app needs to obtain the full data item(s) for given component value(s).

This feature request is applicable to:

• AutoComplete
• ComboBox
• DropDownList
• MultiColumnComboBox
• MultiSelect

Using Microsoft Visual Studio Professional 2022 (64-bit) - Current Version 17.11.0

Trying to create a new Telerik for Blazor project using Telerik C# Blazor Application Template.

Visual Studio freezes after I Name the project and click create. Only way to exit out of Visual Studio is to kill it through task manager.

Trying your project walk through for Blazor, RpsTrackingBlazor, After I add the nuget packages and try to add the using statement to _imports.razor as in the tutorial I get the error that the type or namespace name telerik could not be found.

Your project uses <TargetFramework>netcoreapp3.1</TargetFramework>

I also tried framework net8.0

Hi, I just came accross a bug in the TelerikStepper.

I try to create a custom version that switches to a custom success icon after a step is completed.
It contains the following codesnippets:

<TelerikStepper Linear="true" ValueChanged="@HandleValueChanged">
    <StepperSteps>
        @for (int i = 0; i < IsValidArray.Length; i++)
        {
            <StepperStep Valid="@IsValidArray[i]"></StepperStep>
        }
    </StepperSteps>
</TelerikStepper>

@code {
    bool?[] IsValidArray = [null, null, null, null];

    public void HandleValueChanged(int index)
    {
        for (int i = 0; i < IsValidArray.Length; i++)
        {
            IsValidArray[i] = index > i ? true : null;
        }
    }
}

Forward it works like expected:

When moving backwards it behaves strange:

Except if you are debugging (Visual Studio debugger), then everything works as expected:

Same thing can be achived when not debugging but clicking on the step a second time.


This can not be solved by adding the @key parameter as suggested in https://feedback.telerik.com/blazor/1659827-bug-in-the-telerikstepper-in-blazor from Hristian Stefanov!

Nevertheless, it turns out that the Task.Delay(1); seems to solve the Issue somehow.

Is this intended?

Hi Telerik Team,

when using the (currently) latest versions of VS (17.11.0) and Blazor 8.0.8 runtimes (and custom css theme version 8.2.0) I get the following error when running my project in debug mode:

TypeError: Cannot read properties of null (reading 'classList')
Stapelüberwachung:
 >  at e.addClass (https://localhost:7038/_content/Telerik.UI.for.Blazor/js/telerik-blazor.js:50:1122923)
 >    at v.resetCallout (https://localhost:7038/_content/Telerik.UI.for.Blazor/js/telerik-blazor.js:50:1372516)
 >    at v.adjustCalloutPosition (https://localhost:7038/_content/Telerik.UI.for.Blazor/js/telerik-blazor.js:50:1372355)
 >    at e.invokeComponentMethod (https://localhost:7038/_content/Telerik.UI.for.Blazor/js/telerik-blazor.js:50:1112736)
 >    at https://localhost:7038/_framework/blazor.webassembly.js:1:2878
 >    at new Promise (<anonymous>)
 >    at b.beginInvokeJSFromDotNet (https://localhost:7038/_framework/blazor.webassembly.js:1:2835)
 >    at Object.vn [as invokeJSJson] (https://localhost:7038/_framework/blazor.webassembly.js:1:58849)
 >    at https://localhost:7038/_framework/dotnet.runtime.8.0.8.80cvijctdx.js:3:178428
 >    at Ll (https://localhost:7038/_framework/dotnet.runtime.8.0.8.80cvijctdx.js:3:179262)

It looks like the problem has something to do with a function that wants to set the css "k-callout-e" class to some object.
The problem appears in js when e is null in the following method:
e.classList.add(t)

In this case e = null and t = "k-callout-e". It seems there's no null check for e and VS 2022 reports the problem.

The debugger in VS cannot be disabled for js content as it seems it's the same debugger for Blazor itself.
When hitting F5 to continue multiple times the projects keeps running until it hits the same problem again.

In my project I added a single "TelerikTooltip" component for Tooltips. I tried disabling it but still the same problem.
Maybe the js code is used for some other component.

If you need more information just let me know.

Regards,
Tom