Could not find 'Radzen.preventArrows' ('Radzen' was undefined)

Radzen.Blazor Components
1

In a Radzen Data grid, I get this error with both dates and drop-downs
Here's the drop-down code

<RadzenDataGridColumn TItem="Puppy_Trick" Property="TrainerName" Title="Trainer">
Template Context="trick">
<RadzenDropDown TValue="int" Data=@Trainers TextProperty="TrainerName"
ValueProperty="ID" Value="@trick.TrainerID"/>
</Template>
</RadzenDataGridColumn>

Trainers contains a list of TrainerID and TrainerName

I'm trying to set the Trainer name on the puppy_trick which has the ID of the trainer. All the correct Trainer names are displayed, but I get the error after the page renders making the page inoperable.

With dates, it doesnt even render the page - I get the error before render
<RadzenDataGridColumn TItem="Puppy_Trick" Property="DateLearned" Filterable="true" Title="Date" Width="50px" TextAlign="TextAlign.Left">
<Template Context="trick">
<RadzenDatePicker @bind-Value="trick.DateLearned" Style="width:100%; display: block" Name="Level" />
</Template >
</RadzenDataGridColumn>

DateLearned is a DateTime attribute on the Puppy_Trick object

Other components work fine with the templates

I saw a couple other tickets that suggested refreshing the browser cache but doing so did not help.

Thanks in advance for your suggestions.

Note: My code was not being displayed above So I had to replace all < with &lt ;

2

I suggest you to check our forum FAQ for more info about code formatting and duplicate threads.

3

Thanks for the suggestion I'll re-read the FAQ.

I searched pretty exhaustively about this issue and found a couple of references with the suggestion to clear the browser cache. I did that and did not get those results, and it doesnt describe the root cause of the issue.

I'm hoping someone with a deeper understanding of the library can suggest what's going on - the examples are helpful, but there is not much guidance that can help someone learning the controls figure out what's wrong when they don't work when expected.

Anyway, thanks for taking the time to suggest the FAQ.

4

Can't be a cache error as I installed a copy of Firefox (which was never installed on the computer) and got the error:

Error: Microsoft.JSInterop.JSException: Could not find 'Radzen.preventArrows' ('Radzen' was undefined).

Not sure what's going on - reading the source, I see the method defined in in the JS file and understand its purpose, but dont see why the JSInterop can't find the file when it finds it otherwise.

5

I concede that this was a duplicate issue.

The problem was a very rookie mistake - neglected to include

<script src="_content/Radzen.Blazor/Radzen.Blazor.js"></script>

In my _Hosts.chtml file.

1 Like
6

Thanks for posting what you've found. This helped me out 4 years later.
For those are wondering..., .Net 8 has replace the chtml with App.razor.

7

Hi @jwu,

Make sure to check the getting started too.