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

Examples

Properties

Page or control property

xml

<TextBlock Text="{x:Bind MyProperty}" />

Member function

xml

<TextBlock Text="{x:Bind MyProperty.ToUpper()}" />

Static types field or properties OneTime binding

xml

<TextBlock Text="{x:Bind local:StaticType.PropertyIntValue}" />

OneWay local member function with multiple observable parameters

xml

<TextBlock Text="{x:Bind Multiply(slider1.Value, slider2.Value), Mode=OneWay}" />

OneWay static class function with multiple observable parameters

xml

<TextBlock Text="{x:Bind local:StaticType.Add(slider1.Value, slider2.Value), Mode=OneWay}" />

Literal boolean parameters (x:True, x:False)

xml

<TextBlock Text="{x:Bind BoolFunc(x:False)}" />

Null parameter (x:Null)

xml

<TextBlock Text="{x:Bind TestString(x:Null)}" />

Quote escaping

xml

<TextBlock Text="{x:Bind sys:String.Format('{0}, ^'{1}^'', InstanceProperty, StaticProperty)}" />

Literal numeric value

xml

<TextBlock Text="{x:Bind Add(InstanceProperty, 42.42)}" />

Use of system functions (given xmlns:sys="using:System"):

Single parameter formatting:

xml

<TextBlock Text="{x:Bind sys:String.Format('Formatted {0}', MyProperty), Mode=OneWay}" />

Multi parameters formatting:

xml

<TextBlock Text="{x:Bind sys:String.Format(x:Null, 'slider1: {0}, slider2:{1}', slider1.Value, slider2.Value), Mode=OneWay}" />

TimeParsing:

xml

<CalendarDatePicker Date="{x:Bind sys:DateTime.Parse(TextBlock1.Text)}" />

Use of BindBack

xml

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

where this methods is available in the control:

csharp

public void BindBackMyInteger(string text)
{
  MyInteger = int.Parse(text);
}

Bind to events

xml

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

where these methods are available in the code behind:

csharp

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

Attached Properties

xml

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

Type casts

xml

<TextBox FontFamily="{x:Bind (FontFamily)MyComboBox.SelectedValue}" />

xml

<TextBox Text="{x:Bind (x:String)MyObject}" />

xml

<TextBox Text="{x:Bind MyFunction((x:String)MyObject, (x:String)MyObject)}" />

xml

<TextBox Tag="{x:Bind ((x:String)MyObject).Length}" />

where this methods is available in the code behind:

csharp

public void MyFunction(string p1, string p2) { }

Pathless casting

xml

<Page
  x:Class="AppSample.MainPage"
  ...
  xmlns:local="using:AppSample">

  <Grid>
      <ListView ItemsSource="{x:Bind Songs}">
          <ListView.ItemTemplate>
              <DataTemplate x:DataType="local:SongItem">
                  <TextBlock
                      Margin="12"
                      FontSize="40"
                      Text="{x:Bind local:MainPage.GenerateSongTitle((local:SongItem))}" />
              </DataTemplate>
          </ListView.ItemTemplate>
      </ListView>
  </Grid>
</Page>

x:Load binding
xml
```
<TextBox x:Load="{x:Bind IsMyControlVisible}" />
```
See the {x:Bind} markup extension from WinUI documentation for more details.