The Set button should not be enabled when you change the month from the button in the popup, until the user selects a date too.
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TELERIK EDIT:
If the user clicks Set without selecting a date, the component will assume DateTime.MinValue. You can set the current DateTime or clear the Value by using the DateTimePicker OnChange or ValueChanged event:
<TelerikDateTimePicker @bind-Value="@DateTimePickerValue"
OnChange="@DateTimePickerValueChanged"
Width="300px">
</TelerikDateTimePicker>
@code {
private DateTime? DateTimePickerValue { get; set; }
private void DateTimePickerValueChanged(object currentValue)
{
if (DateTimePickerValue.HasValue && DateTimePickerValue.Value == DateTime.MinValue)
{
// Set current DateTime
DateTimePickerValue = DateTime.Now;
// OR
// Clear the value
//DateTimePickerValue = default;
}
}
}