Checkbox value does not change in dropdownlist onchange event

[Pino]

I have a Telerik Dialog:

 

@using Telerik.Blazor.Components
<TelerikDialog @bind-Visible="@Visible" Width="320px" Title="Submit the page">
    <DialogContent>
        <div id="dialog-form-fileupload">
            <div id="divMessagesFile" class="en-form-row en-message-warning">
            </div>
            <div class="col-md-12">
                <div class="form-group">
                    <InputFile OnChange="@LoadFiles">
                    </InputFile>
                </div>
                <div class="form-group">
                    <label>Documentsoort</label>
                    <div>
                        <TelerikDropDownList Data="@DocumentTypes" TextField="Value" ValueField="Key" @bind-Value="@DocumentType" @ref="@DocumentTypesRef"
                                             OnChange="OnDocumentTypeChanged"></TelerikDropDownList>
                    </div>
                    <div><span>@IsEnabled</span></div>
                </div>
                <div class="form-group">
                    <label>Meesturen naar aannemer</label>
                    <div class="form-check form-check-inline">
                        <TelerikCheckBox id="send-to-contractor" class="form-check-input" @bind-Value="@SentToContractor" Enabled="@IsEnabled" @ref="@SentToContractorRef" />
                    </div>
                </div>

            </div>
        </div>
    </DialogContent>
    <DialogButtons>
        <TelerikButton ButtonType="@ButtonType.Button" class="btn btn-primary ms-2" OnClick="@Save">Opslaan</TelerikButton>
        <TelerikButton ButtonType="@ButtonType.Button" class="btn btn-primary ms-2" OnClick="@Cancel">Annuleren</TelerikButton>
    </DialogButtons>
</TelerikDialog>

 

My problem is with the TelerikDropDownList and the TelerikCheckBox. In my OnDocumentTypeChanged I want to check/unchech and enable/disable the chekbox depending from the selected item in de dropdownlist.

I tried many ways but the checkbox did not change, i even put a span with the value of the IsEnabled, and also that didn't change.

However when I close the popup, and open it again, the values are correctly set
THis is the "close"function

private void Cancel()
    {
        Visible = false;
    }

These are the OnDocumentTypeChanged functions I used but did not work

 public void OnDocumentTypeChanged(object newValue)
    {
        var selectedItem = DocumentTypes.FirstOrDefault(item => item.Key == newValue as string);
        if (selectedItem != null)
        {
            IsEnabled = selectedItem.OpdrachtberichtWijzigbaar;
            SentToContractor = selectedItem.Opdrachtbericht;          
        }
        StateHasChanged();
    }

public async Task OnDocumentTypeChanged(object newValue)
    {
        var selectedItem = DocumentTypes.FirstOrDefault(item => item.Key == newValue as string);
        if (selectedItem != null)
        {
            IsEnabled = selectedItem.OpdrachtberichtWijzigbaar;
            SentToContractor = selectedItem.Opdrachtbericht;          
        }
        await InvokeAsync(StateHasChanged);

         return Task.CompletedTask;

    }

public async Task OnDocumentTypeChanged(object newValue)
    {
        var selectedItem = DocumentTypes.FirstOrDefault(item => item.Key == newValue as string);
        if (selectedItem != null)
        {
            await InvokeAsync(() =>
            {
                IsEnabled = selectedItem.OpdrachtberichtWijzigbaar;
                SentToContractor = selectedItem.Opdrachtbericht;
            });

            // Trigger a UI update
            StateHasChanged();
        }
    }

 

But I always get the same resutl, the checkbox' state is not changed only when i close the dialog and reopen it.

I also tried to close the dialog within the OnDocumentTypeChanged, by putting Visible = false; in it

And strangely, that did work, ANyone knows what I did wrong?

[Hristian Stefanov]

Hi Pino,

Thank you for providing such comprehensive information about what you are experiencing. Now let me share my observations below.

The described issue appears because when there are changes in items inside the Dialog (e.g. - changing components state, loading components data, etc.), the Dialog needs a refresh so it can react to these changes. To do that, use its Refresh() method, which you can access through the Dialog's reference.

As a next step, refresh the component by using the above method inside the "OnDocumentTypeChanged" handler, after the change. 

Let me know if you are still facing any difficulties.

Regards,
Hristian Stefanov
Progress Telerik

[Pino]

Of course!

That was the solution, it is working now. Thank you very much.