The input in the DateTimePicker is valid when:

- the DateTimePicker value is bound to nullable DateTime and

- the user clears the input

In such cases, the input field shouldn't get a red border.

Here is a REPL example to reproduce the issue:

1. Select a date.
2. Clear the date. The input gets a red border.

===ADMIN EDIT===

A possible workaround is to change the border color with CSS. Here is a REPL example.

If you are zooming a page containing a DateTimePicker with "AdaptiveMode" set to "AdaptiveMode.Auto", the application crashes occasionally with the error:

Microsoft.JSInterop.JSException: Cannot read properties of null (reading 'addEventListener')
TypeError: Cannot read properties of null (reading 'addEventListener')

The more adaptive DateTimePicker instances the page contains, the more likely the error is to occur.

Hello,

A Date/Time Picker is bound to a nullable DateTime value. If the user clears the value with the keyboard, the component will show as invalid (with red border). Instead, the picker should treat null values as valid.

Here is a test page with a few different workarounds:

<TelerikButton OnClick="@( () => DateValue = null )">Clear Value</TelerikButton>
<TelerikButton OnClick="@( () => DateValue = DateTime.Now )">Set Value</TelerikButton>

DateValue.HasValue: @DateValue.HasValue

<p>Default behavior:</p>

<TelerikDatePicker @bind-Value="@DateValue"
                   Width="200px" />

<p>Red border will disappear after blur (CSS):</p>

<TelerikDatePicker @bind-Value="@DateValue"
                   Width="200px"
                   Class="@( !DateValue.HasValue ? "valid-null" : "" )" />

<p>Red border will never appear (CSS):</p>

<TelerikDatePicker @bind-Value="@DateValue"
                   Width="200px"
                   Class="valid-null" />

<p>Red border will disappear after blur (OnChange):</p>

<TelerikDatePicker @bind-Value="@DateValue"
                   Width="200px"
                   OnChange="@OnPickerChange" />


<style>
    .k-input.k-invalid.valid-null {
        border-color: rgba(0, 0, 0, 0.08);
    }
</style>

@code {
    private DateTime? DateValue { get; set; } = DateTime.Now;

    private async Task OnPickerChange(object newValue)
    {
        DateTime? newDate = (DateTime?)newValue;

        if (!newDate.HasValue)
        {
            DateValue = DateTime.Now;
            await Task.Delay(1);
            DateValue = null;
        }
    }
}

I've determined that the TelerikDateTimePicker does not work properly on mobile devices when using AdaptiveMode.Auto. Attached are videos of the component's behaviour in both modes (None, and Auto).

Immediately after interacting with the fullscreen popup of the datepicker, I see this error in the console:

RAW:
telerik-blazor.js:50 Uncaught TypeError: r.isParent is not a function
    at p.isChild (telerik-blazor.js:50:1362352)
    at f.closePopup (telerik-blazor.js:50:1398427)
    at HTMLHtmlElement.onMouseDown (telerik-blazor.js:50:1397246)

Code:

@using Telerik.Blazor.Components
@using Telerik.Blazor

<TelerikFloatingLabel Text="Date & Time">
    <TelerikDateTimePicker Id="date-picker" @bind-Value="MyFormModel.Date" Max="@DateTime.Now.AddDays(1)"
                           Format="@DATE_FORMAT" AdaptiveMode="AdaptiveMode.Auto"
                           FillMode="@Telerik.Blazor.ThemeConstants.DateTimePicker.FillMode.Flat" />
</TelerikFloatingLabel>

@code {
    private FormModel MyFormModel { get; set; } = new FormModel();
    private const string DATE_FORMAT = "MM/dd/yyyy HH:mm";

    private class FormModel
    {
        public DateTime Date { get; set; }
    }
}

Notes:
- If we remove all of the parent components wrapping the DatePicker, it seems to function properly, but the errors remain in the console. This isn't a solution, however.

The bug is reproducible only when the TimePicker is bound to a nullable type (be that DateTime or TimeOnly). In this case, selecting time from the popup includes seconds in the value - the seconds from the time of selection. When typing in the input, seconds are always 00.

The issue is that the user is not aware of the seconds' value and cannot change it. This may lead to a variety of problems - e.g. filtering by time in Grid: https://blazorrepl.telerik.com/cebaGNlH53mOoiaA12.

In the TelerikDatePicker, when I select the date and click outside, the event triggers one time only, but when I do the same inside the TelerikDateTimePicker it triggers two times (the first when I set the time and the second when I click outside).

In the end of the ticket I will provide a simple demo code used in Telerik REPL for Blazor comparing the behaviour between the two elements.

Additionally I would like to report the fact that in the TelerikDateTimePicker, when there's no value and I open the calendar and click "Set" without doing anything else, the DateTime is set to "01/01/0001 00:00" instead of null.

Hey Telerik team,

We encountered issue with DateTime picker which I was able to reproduce in your Documentation preview.

If you hover over the date time dropdown, but really slowly it bugs out and the view becomes unusable like this:

As you can see, the dropdown is messed up and it seems like the hover over the border is trying to trigger some action to change from date to time pick automatically

Jakub

Hi.

When entering an invalid date in a DateTimePicker, the component will automatically revert the entered value back to its previous valid value.

I didn't expect this because the user may type in an invalid date, and continue to the next input control within the form, and not notice the error that was briefly displayed.

The issue can be reproduced in the DateTimePicker Demo here: https://demos.telerik.com/blazor-ui/datetimepicker/validation

Steps to reproduce:

1. Click in the day part of the date.

2. Enter 13

3. Enter 2100

4. Press the Tab key

5. Notice the date is automatically reverted (back) to 10/13/2019.

I expected the date to be set to 10/13/2100 with the input validation errors visible to the user after pressing the Tab key in step 4.

I've categorized this issue as a bug because otherwise, the form can be submitted with a value that the user did not enter.

If this behavior cannot be changed from being the default behavior, then there should be an option to prevent this behavior from happening.

Thank you.

Some users report that the hour selector of the datetime picker is not visible. For some people it starts to show if you move the scroll wheel. For some that does not help. This does not happen for all users and can be tricky to replicate. I can replicate it on certain zoom levels and resolutions.

I can replicate this on the demo site. Screenshot added. 

I can also make it work again by removing "translateY(93px)". Screenshot added.

When the component's Adaptive mode is set to Auto, the Date & Time buttons in the popup are not rendered. 

<AdminEdit>

Here is a CSS workaround that hides the titlebar in adaptive mode so that the buttons are present:

<style>
    .k-actionsheet-titlebar.k-text-center{
        display: none;
    }
</style>

<TelerikDateTimePicker @bind-Value="@SelectedTime"
                        Format="MM/dd/yyyy hh:ss"
                        ShowWeekNumbers="true"
                        Id="selected-date"
                        AdaptiveMode="Telerik.Blazor.AdaptiveMode.Auto">
</TelerikDateTimePicker>

@code {
    private DateTime? SelectedTime = DateTime.Now;
}

</AdminEdit>

Hey,

Just reporting this as an active bug. If I have a nullable DateTime object, and I erased the date on the date time picker, it treats the date time field as invalid. I would expect it to be treated as valid.

Related thread: https://feedback.telerik.com/blazor/1582282-datepicker-should-accept-null-value-as-valid-when-bound-to-nullable-datetime

This is the razor page:

DateTimePicker loses focus when the NOW button is clicked. 

To reproduce the problem open the following demo:

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

Try clicking a few times on the NOW button. The focus is occasionally lost. 

https://www.screencast.com/t/BPEXTy43

If you enter a format with a 24 hour time( Format="dd MMM yyyy HH:mm:ss")  for the Timepicker

If you enter the same format for the DateTimePicker the TimePicker in the DateTimePicker looks like this:

It seems like this is a bug as the only way I can change the DateTimePicker time UI is to alter my language/culture whereas the TimePicker displays correctly based on my format. 

I want the user to only be able to select times between, for example, 11AM and 1PM. Setting Min and Max does not limit that, I can select any time: