XAML and Date Picker

[vsfeedback]

This issue has been moved from a ticket on Developer Community.

---

Binding Date = 12Oct19 09:30.
If the XAML page contains a line such as follows:
<DatePicker x:Name="_datePicker" Format="ddMMMyy" Date="{Binding Date}" DateSelected="DatePicker_DateSelected"/>
follwed by the line such as:
<Label x:Name="_timeLabel" Text="{Binding Date, StringFormat='{0:HH:mm}'}"></Label>
the Label _timeLabel will contain the Text: "00:00" instead of the value in the Binding Date Time if _datePicker was not used.

This is because the _datePicker even though not used has updated the Binding Date to it's Default Time Value of "00:00".

Reversing the lines to read:
<Label x:Name="_timeLabel" Text="{Binding Date, StringFormat='{0:HH:mm}'}"></Label>
<DatePicker x:Name="_datePicker" Format="ddMMMyy" Date="{Binding Date}" DateSelected="DatePicker_DateSelected"/>
will now show "09:30" in the Label _timeLabel.

This is an important fault of Date Picker, and I think Time Picker may also have this problem where if not use they fill the Binding Field with their Default Values.

---

Original Comments

Visual Studio Feedback System on 10/21/2019, 04:53 AM:

We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.

---

Original Solutions

(no solutions)

[hartez]

Added a repro project. Note that the first Label shows the correct value; the label after the DatePicker shows the incorrect value.

Maybe the binding/formatting in DatePicker is truncating the DateTime value?

_8338 Repro.zip

[memsranga]

Works fine with BindingMode set to OneWay on DatePicker.
So the Picker is messing with the bindings!

[nysand]

I have a similar problem that came up today with my DatePicker in xamarin forms.

<DatePicker Grid.Row="0" Grid.Column="0" x:Name="expenseDate" DateSelected="ExpenseDate_DateSelected" Date="{Binding DocumentDate, StringFormat='{0:dd/MM/yyyy}', Mode=OneWay}" IsVisible="False" HorizontalOptions="CenterAndExpand"></DatePicker>

<Label x:Name="dteDocumentDate" Text="{Binding DocumentDate, StringFormat='{0:dd/MM/yyyy}', Mode=OneWay}" VerticalOptions="CenterAndExpand" HorizontalOptions="StartAndExpand" Margin="10,0,0,0" Style="{StaticResource LabelFieldStyle}"></Label>

Although the date specified in my label is 1/11/2019, in reality the date in the DatePicker is 11/1/2019. Somehow the date picker is mixing up the day with the month. If i take out the mode=OneWay from the picker every time i click on a day that between 1 and 12 it mixes up the day with month if it's a day from 13 to 31 it recognise that i selected the day.

If i format my day to MM/dd/yyyy everything works nicely just for the dd/MM/yyyy format is not working.

[jcmanke]

The DateProperty, MinimumDateProperty, and MaximumDateProperty of DatePicker all have CoerceValueDelegates that only take the Date property of the new value, thus clearing the time component.

DateTime dateValue = ((DateTime)value).Date;

[hartez]

@nysand I think what you are seeing is a different problem - you should open up a new issue.

[gmwilhelm]

@hartez Any news on this one?

[MhAllan]

2021 .. datepicker date doesn't bind unless you set Mode=OneWay