Binding is not working for property which is of DateTimeOffset? Type

[mageshsankar]

Describe the bug I am trying to bind value for property of nullable DateTimeOffset type, but binding does not work. But, when I manually set the value for particular property in code behind, it works properly. Please find the Code Snippet for the same below:

Expected behavior Binding Should work as expected

XAML:

<Page x:Class="BindingIssue_sample.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="using:BindingIssue_sample" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">

C#: public class ViewModel : INotifyPropertyChanged { private DateTimeOffset dateTime = new DateTimeOffset(new DateTime(2019, 1, 1)); public DateTimeOffset? SelectedDateTime { get { return dateTime; } set { dateTime = value.Value; this.RaisePropertyChanged(nameof(this.SelectedDateTime)); } } ///

/// Raised when a property on this object has a new value. ///

public event PropertyChangedEventHandler PropertyChanged; ///

/// Raises this object's PropertyChanged event. ///

/// The property that has a new value. protected virtual void RaisePropertyChanged(string propertyName) { if (this.PropertyChanged != null) { this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } } public class CustomPicker : Control { public DateTimeOffset? NullableDateTime { get { return (DateTimeOffset?)GetValue(NullableDateTimeProperty); } set { SetValue(NullableDateTimeProperty, value); } } // Using a DependencyProperty as the backing store for MyProperty. This enables animation, styling, binding, etc... public static readonly DependencyProperty NullableDateTimeProperty = DependencyProperty.Register("NullableDateTime", typeof(DateTimeOffset?), typeof(CustomPicker), new PropertyMetadata(null, OnDateTimeChangedAsync)); ///

/// Occurs when the property is changed. ///

/// The d. /// The e. private static async void OnDateTimeChangedAsync(DependencyObject sender, DependencyPropertyChangedEventArgs args) { var dialog = new MessageDialog("Nullable DateTime property value changed"); _ = await dialog.ShowAsync(); } } **Version Info** NuGet package version: Windows app type: | UWP | Win32 | | :--------------- | :--------------- | | Yes | | | Windows 10 version | Saw the problem? | | :--------------------------------- | :-------------------- | | Insider Build (xxxxx) | | | May 2020 Update (19041) | Yes | | November 2019 Update (18363) | | | May 2019 Update (18362) | | | October 2018 Update (17763) | | | April 2018 Update (17134) | | | Fall Creators Update (16299) | | | Creators Update (15063) | | | Device form factor | Saw the problem? | | :----------------- | :--------------- | | Desktop | Yes | | Xbox | | | Surface Hub | | | IoT | | **Additional context**

[StephenLPeters]

@mageshsankar did you find this issue using Winui3 or system xaml (winui2)?

[mageshsankar]

Hi @StephenLPeters

I have found the issue in WinUi 3

Thanks

[stevenbrix]

@mageshsankar does this work with x:Bind? And do you know if it's just DateTimeOffset or is it any nullable type?

[mageshsankar]

@stevenbrix issue occurs only for nullable type, as you suggested x:Bind is working properly for nullable DateTimeOffset ,

The same scenario(binding) working properly for nullable DateTime type.

Issue only with nullable DateTimeOffset type

[mageshsankar]

Hi Team,

Is there any workaround solution to resolve the binding issue in custom control(CustomPicker) itself instead of using x:bind in application level.

[mageshsankar]

Hi Team,

Any update on this?

[wbokkers]

I can't x:Bind the Date property of CalendarDatePicker to DateTimeOffset (nullable or not), without getting an exception in WinUI 3 Preview 4

[tanothing]

Hi Team, Any update on this issue? I had same issue with Nullable DateTime too. I cannot bind string to LowerValue on XAML. Please take a look at this issue. Thanks! [DefaultValue(typeof(DateTime), "")] public DateTime? LowerValue { get => _lowerValue; set => SetLowerValue(value, false); }

[sethuramkumar]

Hi Team, Any updates on the above issue? Any workaround/fix instead of using x;Bind ?