Attached Properties

July 14, 2026 · View on GitHub

Attached properties are defined on one type but set on instances of other types — Grid.Row, Shell.TitleColor, SemanticProperties.Hint, and so on. FmgLib.MauiMarkup maps each one to a fluent method so they read like normal properties.

Quick Example

// XAML:  <Border AbsoluteLayout.LayoutBounds="100,100,200,200" />
new Border().AbsoluteLayoutBounds(new Rect(100, 100, 200, 200));

// convenience overload without constructing a Rect:
new Border().AbsoluteLayoutBounds(100, 100, 200, 200);

Complete Mapping Table

Grid

MAUI attached property	Fluent method
`Grid.Column`	`Column()`
`Grid.Row`	`Row()`
`Grid.ColumnSpan`	`ColumnSpan()`
`Grid.RowSpan`	`RowSpan()`
`Grid.ColumnSpan` + `Grid.RowSpan`	`GridSpan(column, row)`

new Image().Row(0).Column(1).RowSpan(2)

AbsoluteLayout

MAUI attached property	Fluent method
`AbsoluteLayout.LayoutFlags`	`AbsoluteLayoutFlags()`
`AbsoluteLayout.LayoutBounds`	`AbsoluteLayoutBounds()`

new AbsoluteLayout().Children(
    new BoxView()
        .Color(Colors.Teal)
        .AbsoluteLayoutFlags(AbsoluteLayoutFlags.PositionProportional)
        .AbsoluteLayoutBounds(new Rect(0.5, 0.5, 100, 100))   // centered, 100×100
)

BindableLayout (on any layout)

MAUI attached property	Fluent method
`BindableLayout.ItemsSource`	`BindableLayoutItemsSource()`
`BindableLayout.ItemTemplate`	`BindableLayoutItemTemplate()`
`BindableLayout.TemplateSelector`	`BindableItemTemplateSelector()`
`BindableLayout.EmptyView`	`BindableLayoutEmptyView()`
`BindableLayout.EmptyViewTemplate`	`BindableLayoutEmptyViewTemplate()`

See Collections & Templates for full examples.

RadioButton groups

MAUI attached property	Fluent method
`RadioButtonGroup.GroupName`	`RadioButtonGroupGroupName()`
`RadioButtonGroup.SelectedValue`	`RadioButtonGroupSelectedValue()`

new VerticalStackLayout()
    .RadioButtonGroupGroupName("Sizes")
    .RadioButtonGroupSelectedValue(e => e.Path("SelectedSize").BindingMode(BindingMode.TwoWay))
    .Children(
        new RadioButton().Content("S").Value("S"),
        new RadioButton().Content("M").Value("M"),
        new RadioButton().Content("L").Value("L")
    )

MAUI attached property	Fluent method
`FlyoutBase.ContextFlyout`	`ContextFlyout()`

See Menus.

VisualStateManager

MAUI attached property	Fluent method
`VisualStateManager.VisualStateGroups`	`VisualStateGroups()`

See Visual States.

Shell (set on pages/items)

MAUI attached property	Fluent method
`Shell.PresentationMode`	`ShellPresentationMode()`
`Shell.BackgroundColor`	`ShellBackgroundColor()`
`Shell.ForegroundColor`	`ShellForegroundColor()`
`Shell.TitleColor`	`ShellTitleColor()`
`Shell.DisabledColor`	`ShellDisabledColor()`
`Shell.UnselectedColor`	`ShellUnselectedColor()`
`Shell.NavBarHasShadow`	`ShellNavBarHasShadow()`
`Shell.NavBarIsVisible`	`ShellNavBarIsVisible()`
`Shell.TitleView`	`ShellTitleView()`
`Shell.TabBarBackgroundColor`	`ShellTabBarBackgroundColor()`
`Shell.TabBarForegroundColor`	`ShellTabBarForegroundColor()`
`Shell.TabBarTitleColor`	`ShellTabBarTitleColor()`
`Shell.TabBarDisabledColor`	`ShellTabBarDisabledColor()`
`Shell.TabBarUnselectedColor`	`ShellTabBarUnselectedColor()`
`Shell.TabBarIsVisible`	`ShellTabBarIsVisible()`
`Shell.FlyoutBackdrop`	`ShellFlyoutBackdrop()`
`Shell.FlyoutBehavior`	`ShellFlyoutBehavior()`
`Shell.FlyoutHeight`	`ShellFlyoutHeight()`
`Shell.FlyoutWidth`	`ShellFlyoutWidth()`
`Shell.FlyoutItemIsVisible`	`ShellFlyoutItemIsVisible()`
`Shell.BackButtonBehavior`	`ShellBackButtonBehavior()`
`Shell.ItemTemplate`	`ShellItemTemplate()`
`Shell.MenuItemTemplate`	`ShellMenuItemTemplate()`
`Shell.SearchHandler`	`ShellSearchHandler()`

Example — hide the nav bar and tab bar on a login page:

public partial class LoginPage : ContentPage, IFmgLibHotReload
{
    public LoginPage() => this.InitializeHotReload();

    public void Build() =>
        this
        .ShellNavBarIsVisible(false)
        .ShellTabBarIsVisible(false)
        .Content(/* ... */);
}

NavigationPage (set on pages)

MAUI attached property	Fluent method
`NavigationPage.HasNavigationBar`	`NavigationPageHasNavigationBar()`
`NavigationPage.BackButtonTitle`	`NavigationPageBackButtonTitle()`
`NavigationPage.HasBackButton`	`NavigationPageHasBackButton()`
`NavigationPage.IconColor`	`NavigationPageIconColor()`
`NavigationPage.TitleIconImageSource`	`NavigationPageTitleIconImageSource()`
`NavigationPage.TitleView`	`NavigationPageTitleView()`

Accessibility — Semantic & Automation

MAUI attached property	Fluent method
`SemanticProperties.Hint`	`SemanticHint()`
`SemanticProperties.Description`	`SemanticDescription()`
`SemanticProperties.HeadingLevel`	`SemanticHeadingLevel()`
`AutomationProperties.ExcludedWithChildren`	`AutomationExcludedWithChildren()`
`AutomationProperties.IsInAccessibleTree`	`AutomationIsInAccessibleTree()`
`AutomationProperties.Name`	`AutomationName()`
`AutomationProperties.HelpText`	`AutomationHelpText()`
`AutomationProperties.LabeledBy`	`AutomationLabeledBy()`

new Image()
    .Source("logo.png")
    .SemanticDescription("Company logo")
    .SemanticHint("Decorative image at the top of the page")

new Label()
    .Text("Settings")
    .SemanticHeadingLevel(SemanticHeadingLevel.Level1)

Tooltips

MAUI attached property	Fluent method
`ToolTipProperties.Text`	`ToolTipPropertiesText()`

new Button().Text("?").ToolTipPropertiesText("Opens the help center")

Naming Convention

The rule of thumb for guessing a method name:

Grid placement drops the owner prefix: Grid.Row → Row().
Everything else concatenates owner + property: Shell.TitleColor → ShellTitleColor(), SemanticProperties.Hint → SemanticHint(), AutomationProperties.Name → AutomationName().

The same convention is used for third-party attached properties generated by [MauiMarkupAttachedProp] — e.g. InputKit's FormView.IsSubmitButton becomes FormViewIsSubmitButton().

Builder Support

Attached-property methods accept the property builder lambda like any other property, so bindings and theme/platform values work:

new ContentPage()
    .ShellTabBarIsVisible(e => e.Path("IsTabBarVisible"))
    .ShellBackgroundColor(e => e.OnLight(Colors.White).OnDark(Colors.Black))

Grid
Shell Applications
Third-Party Controls — generating methods for external attached properties