I think I found a bug in all components that use AnimationGroupBase.
How you can reproduce it...

Navigate to a page that has a component that uses AnimationGroupBase - in my case TreeView.

Hit refresh (F5) a couple of times

Wait about 60 seconds and you will get an exception from the title..

The problem is AnimationGroupBase. It has a async void Dispose method. Please fix it to be just void.

Here is a stack trace.

Microsoft.AspNetCore.Components.Server.Circuits.CircuitHost: Error: Unhandled exception in circuit 'uU2u6m_DXs2TW1iUNDEpwJB235BzcJVRHTXjF8kbbaU'.

System.Threading.Tasks.TaskCanceledException: A task was canceled.
   at Microsoft.JSInterop.JSRuntime.InvokeWithDefaultCancellation[T](String identifier, Object[] args)
   at Telerik.Blazor.Components.AnimationContainer.AnimationGroupBase.Dispose()
   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)

Hi,

I have just updated to v2.3 but I dont see version 2.4 in my NuGet package manager. I have check "Include prerelease" but I get "No packages found". I have updated all my Microsoft.AspNetCore.* packages to 3.1.0.-preview3.19555.2

Upgraded to the latest and am getting these errors.

Project builds and so far seems to function regardless.

SeverityCodeDescriptionProjectFileLineSuppression State
ErrorCS0234The type or namespace name 'Shared' does not exist in the namespace 'PurchaseRequest' (are you missing an assembly reference?)PurchaseRequestC:\Users\rjd\source\repos\PurchaseRequest\PurchaseRequest\Pages\Index.razor1Active
ErrorCS0246The type or namespace name 'MainLayout' could not be found (are you missing a using directive or an assembly reference?)PurchaseRequestC:\Users\rjd\source\repos\PurchaseRequest\PurchaseRequest\Pages\Index.razor1Active
ErrorCS0234The type or namespace name 'Shared' does not exist in the namespace 'PurchaseRequest' (are you missing an assembly reference?)PurchaseRequestC:\Users\rjd\source\repos\PurchaseRequest\PurchaseRequest\Pages\Index.razor1Active

I'm trying to change the content of a GridCommandButton based upon a value from the current row - 

I was thinking it would be something like this:

<GridCommandButton Command="Custom" Icon="edit" OnClick="@DisableIntegrator">

<Template>
@{
var integrator = context as Integrator;
integrator.IsActive ? "Deactivate" : "Activate";
}
</Template>



</GridCommandButton>

Hi

I'm currently running a trial of Blazor UI, taking a look at the Grid and Virtual Scrolling.  I've noticed a fairly heavy performance issue on chromium based browsers, bad enough that I wouldn't be able to release to production in it's current state.  My project is Server Side Blazor and the performance issues seem related to mouse over/move, my grid currently only has a single item in it so no actual scrolling happening.  I've tried with asp core 3.0 and 3.1 preview.

Firefox and MS Edge 44 runs the page just fine.

CPU usage for the Tab is very high during mouse movement and when taking a look at the browser tools Performance profiler a very long amount of time is spent Recalculating Styles and Updating the Layer Tree as attached.

Anyone had experience with similar issues or know of a fix?

Regards

Ben

Hi,

Here's what I want to do

@for (int i = 0; i < 14; i++)
{
    <GridColumn Field="@CellDate + (i + 1).ToString()" Title="@SelectedStartDate.AddDays(i).ToShortDateString()" />
}

But I can't seem to get it to compile. It throws and error:

 error RZ9986: Component attributes do not support complex content (mixed C# and markup).

So I get that it doesn't support complex content. I can easily put one line per field, but I don't know the title until runtime. How to set the title as desired?

Is there a way to throw this in a loop at all?

Thanks … Ed

Hi,

Right now in my treeview the default behaviour seems to be that when the mouse goes over an item it is highlighted and when it leaves it's "unhighlighted".

I'd like to be able to have the highlighted state be sticky when a user selects/clicks/expands an item. This is to make it clear to the user which item is currently selected. Currently if the mouse leaves the item, it is no longer highlighted. I guess that would mean that when they move the mouse over other items that are NOT selected there would be 2 items highlighted: the one that is currently selected and the one that is hovered over. So if they clicked on the new item, the "old" selected item gets unhighlighted.

I'm certain there is some css gibberish that can do this, but I'm equally certain that my feeble mind can't quite figure it out.

Any help would be greatly appreciated.

Thanks … Ed

Any tips to maximize performance of filtering larger data sets? In my testing I am experiencing lag when filtering (gif available at https://raw.githubusercontent.com/austineric/Misc/master/Demo.gif).

In the gif example:

• GridDataSource is IEnumerable<TechnicanDataEntryExtension>
• GridDataSource holds 500,000 records
• I am typing the word "hearing"
• I am running the the app locally from visual studio so web server latency isn't involved, I would expect lag to be worse there

I can implement workarounds to decrease the number of records in the grid but in the event where I need to give it larger numbers of records are there any best practices or recommendations to minimize filter lag?

Hello,

i used telerik ui for blazor in a sample project and i used drop downs now i made another project im configured my blazor app but i cant use components with pop up parts( drop down , time picker , ...) and i also checked here  but unfortunately it could'nt fix my problem i checked all the files it same as my last project but now i can't used these types of components 
im using .NET version 3.1.100-preview1-014459
with telerik trial version 2.3.0


this is my _Host.cshmtl

<html lang="en">
<head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Management</title>
    <base href="~/" />
    <link rel="stylesheet" href="css/bootstrap/bootstrap.min.css" />
    <link rel="stylesheet" href="https://unpkg.com/@@progress/kendo-theme-default@@latest/dist/all.css" />
    <link href="css/site.css" rel="stylesheet" />
</head>
<body>
    <app>
        @(await Html.RenderComponentAsync<App>(RenderMode.Static))
    </app>
    <script src="_content/telerik.ui.for.blazor.trial/js/telerik-blazor.js"></script>
    <script src="_framework/blazor.server.js"></script>    

</body>
</html>

and this is my MainLayout.razor

@inherits LayoutComponentBase
<TelerikRootComponent>
    <div class="sidebar">
        <NavMenu />
    </div>

    <div class="main">
        <div class="top-row px-4">
            <a href="https://docs.microsoft.com/aspnet/" target="_blank">About</a>
        </div>

        <div class="content px-4">
            @Body
        </div>
    </div>
</TelerikRootComponent>

i also added
            services.AddTelerikBlazor();
to my Startup.cs

and i added these 
@using Telerik.Blazor
@using Telerik.Blazor.Components
in my _imports.razor