Hi all,

 

I've been observing a strange behavior and cannot seem to find out what causes it. This is primarily to collect some general ideas and learn about principles that I may have missed. I hate to say it but the fact I'm posting it here already suggests that Telerik Blazor UI might be involved, even if it is only by me using it wrong. Before I switched (from Bootstrap UI) to Telerik's Blazor UI, the solution operated more swiftly but was optically inconsistent if not outright ugly. Using Telerik Blazor UI introduced the desired consistency and working with the components is mostly a breeze. I don't regret my choice at all, and will do whatever is needed to keep it part of the solution.

For more context: this is about a multi-layered Blazor app (ASP.NET Core 8) using Telerik's Blazor UI to give users CRUD operations on medical case data. It is supposed to show data from an Oracle relational database with Entity Framework (EF Core 8). It's a data-first approach so I have built entity classes representing each table (about 30 tables in total now) and configured their relations mostly manually. But that's not actually the point. It's just to describe why I can't just paste a small code snippet here. It's a medical application so I'm legally unable to paste code 1:1 from my solution, and it's tons of code by now. Hope the description I'm giving below is enough to put you in the frame.

There are multiple Razor pages and components, some with more and some with less complexity:

• entry pages where users select a quarter and doctor's office
• next page reveals the cases that need work
• selecting a case will go to the editor Blazor page which:
  • shows case basic data such as patient, insurance, summary
  • shows relational positional data in up to four separate grids (Telerik Data Grid) which are encapsulated in Razor components again to keep the main page as slim as possible
  • allows CUD operations and validations on relatonal data
  • uses models to do real-time calculations when users are modifying data
  • uses a persistence layer to collect changes and update storage

The editor page (the heaviest piece of the solution) features:

• a Telerik menu bar
• a Telerik breadcrumb bar
• a Telerik dock manager
• up to 8 dock panes, half containing Razor components rendering HTML tables, the other half being Telerik data grids
• some interaction between DockManager and menu bar for menu items to control the visibility and arrangement of panes
• lots of Telerik(MultiColumn)ComboBox, TelerikTextBox, TelerikDatePicker, TelerikNumericTextBox, TelerikMaskedTextBox etc. inside the panes for data representation and editing

All pages use InteractiveServer render mode as that is what I found works best for me. Until now, the software is only running on my dev machine in Visual Studio 2022, and most of the time in debug mode.

IMPORTANT: Let me emphasize that what I am describing here appears exclusively in debug mode as long as VS2022 is attached, and not when the solution is run by dotnet run. It's a p.i.t.a. though to debug with the handbrake engaged, and I'm not sure if the process does not hide a problem even when it runs without a debugger attached. It's just much faster then but that's not proof that whatever issue it is only affects the debug scenario.

The problems begin when I start navigating between the pages. Sometimes it's really fast, sometimes the same thing takes a lot of time. In my perception it might be related to how quickly I navigate but the actual trigger for the behavior is mostly unclear at this time. Heavier pages cause longer delays (and more exceptions along the way), while being loaded as well as while navigating away from them. But it's not consistent enough to point to an overall page or DOM size-related issue.

What struck me is that the debug console gets flooded with errors like these as delays are happening:

Exception thrown: 'Microsoft.JSInterop.JSDisconnectedException' in Microsoft.JSInterop.dll
Exception thrown: 'Microsoft.JSInterop.JSDisconnectedException' in System.Private.CoreLib.dll
Exception thrown: 'Microsoft.JSInterop.JSDisconnectedException' in System.Private.CoreLib.dll
Exception thrown: 'Microsoft.JSInterop.JSDisconnectedException' in Microsoft.AspNetCore.Components.Server.dll

The one from System.Private.CoreLib.dll appears twice most of the time, sometimes only once. A block like this is shown repeatedly up to 90 times in quick succession, in worse cases, sometimes only ten of these blocks appear in the console. But it's always this combination of the same three DLLs being addressed. When this happens, no other exceptions mix in, it's a constant stream of these three / four exceptions. The application is massively slowed down as this happens. Not as much as showing me a waiting indicator and reconnecting in the page though.

What's also interesting is that the user-end of the solution, besides being very slow at times, behaves fully normally. There are no errors or exceptions apparent to the user. To me this looks like the exceptions are silently consumed somewhere without giving further detail. Each occurrence takes some processing time. I can't say where the exceptions are thrown - probably somewhere deep inside the JS layers - but it's really unsettling and I have some doubts about moving this to production unless this is clarified a bit better.

The Edge browser's developer tools show nothing unusual. The JavaScript console there stays error-free, and running a network recording during a page refresh does show that loading takes very long (about 5 out of 10 seconds are spent with no traffic at all), but all HTTP operations have status 101 (switching protocols) or 200 (success). No error indication at all there.

I beg your pardon for being too unspecific where it may count but this is honestly my first Blazor application at all, and it's a monster of a project right away. I'm overwhelmed by the time pressure already and there's no team mates to help out. Random delays are the last thing I need.

So to wrap this up, what I'm looking for is basically guidance like:

• is ServerInteractive (and no prerendering) a preferable mode to use globally?
• do I have to clean up anything? I was hoping the Telerik components would take care of their memory allocations and connections on their own. If that's wrong or not enough, is IDisposable the way to go? What would have to be forcefully disposed?
• are there any typical no-nos about Blazor apps that I might have missed, such as exceeding a hidden limit regarding the amount of HTML elements in the DOM, or having to keep the number of data grids to a minimum? Could two-way bindings be a root cause? (I'm using them a lot)
• I'm using async wherever it makes sense, assuming that's the way to go nowadays. Anthing special about Blazor regarding async?
• sometimes, I need to call StateHasChanged() to ensure the UI is up-to-date. This may indicate I'm missing a cleaner way to achieve the same, however, I couldn't find anything about this yet

Thank you all for reading, and in advance for any clues.

Cheers, have a nice day!

Joe

Hi,

 

Is there a way to open a date picker component targeting the month of a future minimum date ?

For example, I have a minimum date in 3 months. When I open the date picker, the popup is focus on today. When I change the month or click on 'Today', the focus goes on the month of this future date as expected.

I would like to have this behavior when opening the popup.

I tried to use the NavigateTo() with the OnOpen() event but no luck.

REPL example : https://blazorrepl.telerik.com/cJYCGmlk51WrceTj48

 

Thanks in advance

Hello,

I noticed that when TelerikDatePicker and TelerikTimePicker components are used with nullable DateOnly and nullable TimeOnly values, respectively, and ShowClearButton is set to true, the "X" button still appears in an empty field when the value is null. This shouldn’t happen, as there is no value to clear. When you click on the field to type a date or time, the "X" button disappears.

Here is the reproduction of the issue:

https://blazorrepl.telerik.com/GfaCbmlz03hT2mky54

It doesn’t seem like this is intended behavior. If it’s not, is there a workaround to prevent the "X" from appearing when there is no value?

Thanks,

Ivaylo

 

Hello:

As the subject line states, is there a way to open the DatePicker programmatically?

i am using TelerikDatePicker. I want to use user's timezone based date which i am getting in "OnAfterRenderAsync" but the telerikdatepicker is mixing up between server's date and user's timezone based date.
when i click today instead of selecting user's timezone based date(3 july), it selects the server based date i-e 2 july (which is different). Moreoever, as per in attached image user's timezone based date is 3 july 2025 and server's date is 2 july 2025 and the font of 2 july 2025 is red however the highlighter has moved to 3 july 2025.
I want the datepicker to use  user's timezone based date and deal it like it has been dealing with server's date.

this is my razor page
<TelerikDatePicker Format="dd-MMM-yyyy"
                   @bind-Value="@abc.rcvdDateDW"
                   Enabled="@isDetailEditable"
                   OnOpen="OnDatePickerOpenDW"
                   OnClose="OnDatePickerCloseDW" />

this is how i am setting things up in my razor.cs
    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender && !_initialized)
        {
            _initialized = true;

            try
            {
                var userTimeZoneId = await tokenStorage.GetTokenAsync(UserTimeZoneInfokey);
                var timeZoneId = string.IsNullOrWhiteSpace(userTimeZoneId) ? "UTC" : userTimeZoneId;
                TimeZoneInfo userTimeZone = TimeZoneInfo.FindSystemTimeZoneById(timeZoneId);
                userTimeInTimeZone = TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, userTimeZone);
            }
            catch
            {
                userTimeInTimeZone = DateTime.UtcNow; // fallback
            }
 await ShowData();
 InitializeTabsBasedOnPermissions();
 await Tasks();

 StateHasChanged();
}}
       public async Task OnDatePickerOpenDW(DatePickerOpenEventArgs args)
       {
           if (abc.rcvdDateDW == null && !isTempDateDWReceived)
           {
               abc.rcvdDateDW = userTimeInTimeZone;
               isTempDateDWReceived = true;
               StateHasChanged();
           }
       }
       public async Task OnDatePickerCloseDW(DatePickerCloseEventArgs args)
       {
           if (isTempDateDWReceived && abc.rcvdDateDW == userTimeInTimeZone)
           {
               abc.rcvdDateDW = null;
               isTempDateDWReceived = false;
               StateHasChanged();
           }
       }

thats the output i am getting 

Does telerikdatepicker do support this or not ? if yes kindly guide me how can i achieve this. I have tried many ways but none of them worked. Thanks

Hy,

is there a way to customize the template visualization of each day in the DatePicker component?

I need to change the style and colors of the days according to different conditions. For examples:

 

Thanks in advance

 

I have a custom grid filter where I use an animation container to show/hide.  When a value changes, I want to close the animation container similar to how the filter automatically closes on your control filters (treelist).  So, I have a button that toggles the filter state (ExpandCollapse).  Then, when a value changes in my filter (textbox in example) I call a method that should close the filter and refresh my data.  I find the OnChange event is called once a value is changed (textbox) but then also when the DatePicker closes and when the DropDownList closes and when the animation container is closed.  

The result is the toggle kinda goes nuts.  Its open/closed/opened at times where it shouldn't.  How do I get around this?


I tried to compare the existing value with the new value after removing the binding but, no success.

Toggle

We have a Blazor DatePicker in our web app to store the Date of Birth.  The calendar popup seems to be working correctly.  However, for the input portion, when typing in the year of the date, the content typed into the year overflows the input area for as long as the user types, instead of horizontally scrolling within the 4-digit year space.

The interesting thing is that this is only happening to one of our client users.  We have been unable to duplicate this either locally or in our Dev/Test environments.  I'm assuming that, since the horizontal scrolling of the year entry is within the DatePicker widget, could this possibly be due to an environment issue with the Blazor library or maybe some setting within Microsoft Edge?

I don't have as many details as I would like to have to share with you.  At this time, I'm just trying to find out if you have ever heard of this issue before?

Hi i have a DatePicker in a module form. If i resize the browser window in order to have low visible space below the datepicker, then i open the datepicker popup, it create a strange effect on the page.

For example i have this page with a datepicker (highligted in red):

if i open the datepicker popup the dom change adding white space on bottom of the page:

closing the popup, the white space disappear.

How to solve?

Thanks

 

 

I am working on a mobile app using Blazor Hybrid, I have a TelerikDatePicker field on a page. 
Is there a practical way when I focus on that field it automatically shows the numeric keyboard instead of alphanumeric keyboard ? like when using TelerikNumericTextBox.

Thank you.