Uno Support for x:Bind

Uno supports the x:Bind WinUI feature, which gives the ability to:

  • bind to normal fields and properties
  • static classes fields
  • functions with multiple parameters
  • events
  • x:Bind on "Plain-old C# Objects" (POCO) created in XAML


  • Properties

    • Page or control property
    <TextBlock Text="{x:Bind MyProperty}" />
    • Member function
    <TextBlock Text="{x:Bind MyProperty.ToUpper()}" />
    • Static types field or properties OneTime binding
    <TextBlock Text="{x:Bind local:StaticType.PropertyIntValue}" />
    • OneWay local member function with multiple observable parameters
    <TextBlock Text="{x:Bind Multiply(slider1.Value, slider2.Value), Mode=OneWay}" />
    • OneWay static class function with multiple observable parameters
    <TextBlock Text="{x:Bind local:StaticType.Add(slider1.Value, slider2.Value), Mode=OneWay}" />
    • Literal boolean parameters (x:True, x:False)
    <TextBlock Text="{x:Bind BoolFunc(x:False)}" />
    • Null parameter (x:Null)
    <TextBlock Text="{x:Bind TestString(x:Null)}" />
    • Quote escaping
    <TextBlock Text="{x:Bind sys:String.Format('{0}, ^'{1}^'', InstanceProperty, StaticProperty)}" />
    • Literal numeric value
    <TextBlock Text="{x:Bind Add(InstanceProperty, 42.42)}" />
  • Use of system functions (given xmlns:sys="using:System"):

    • Single parameter formatting:
      <TextBlock Text="{x:Bind sys:String.Format('Formatted {0}', MyProperty), Mode=OneWay}" />
    • Multi parameters formatting:
      <TextBlock Text="{x:Bind sys:String.Format(x:Null, 'slider1: {0}, slider2:{1}', slider1.Value, slider2.Value), Mode=OneWay}" />
    • TimeParsing:
      <CalendarDatePicker Date="{x:Bind sys:DateTime.Parse(TextBlock1.Text)}" />
  • Use of BindBack

    <TextBlock Text="{x:Bind sys:String.Format('{0}', MyInteger), BindBack=BindBackMyInteger, Mode=TwoWay}" />

    where this methods is available in the control:

    public void BindBackMyInteger(string text)
      MyInteger = int.Parse(text);
  • Bind to events

    <CheckBox Checked="{x:Bind OnCheckedRaised}" Unchecked="{x:Bind OnUncheckedRaised}" />

    where these methods are available in the code behind:

    public void OnCheckedRaised() { }
    public void OnUncheckedRaised(object sender, RoutedEventArgs args) { }
  • Attached Properties

    <Button x:Name="Button22" Content="Click me!" Grid.Row="42" />
    <TextBlock Text="{x:Bind Button22.(Grid.Row)}" />
  • Type casts

    • <TextBox FontFamily="{x:Bind (FontFamily)MyComboBox.SelectedValue}" />
    • <TextBox Text="{x:Bind (x:String)MyObject}" />
    • <TextBox Text="{x:Bind MyFunction((x:String)MyObject, (x:String)MyObject)}" />
    • <TextBox Tag="{x:Bind ((x:String)MyObject).Length}" />

    where this methods is available in the code behind:

    public void MyFunction(string p1, string p2) { }
  • Pathless casting

          <ListView ItemsSource="{x:Bind Songs}">
                  <DataTemplate x:DataType="local:SongItem">
                          Text="{x:Bind local:MainPage.GenerateSongTitle((local:SongItem))}" />
  • x:Load binding

    <TextBox x:Load="{x:Bind IsMyControlVisible}" />

    See the WinUI documentation for more details.