OnPlatformExtension Class

Definition

public ref class OnPlatformExtension : Microsoft::Maui::Controls::Xaml::IMarkupExtension

[Microsoft.Maui.Controls.ContentProperty("Default")]
[Microsoft.Maui.Controls.Xaml.RequireService(new System.Type[] { typeof(Microsoft.Maui.Controls.Xaml.IProvideValueTarget), typeof(Microsoft.Maui.Controls.Xaml.IValueConverterProvider), typeof(Microsoft.Maui.Controls.Xaml.IXmlLineInfoProvider), typeof(Microsoft.Maui.Controls.Xaml.IConverterOptions) })]
public class OnPlatformExtension : Microsoft.Maui.Controls.Xaml.IMarkupExtension

[Microsoft.Maui.Controls.ContentProperty("Default")]
public class OnPlatformExtension : Microsoft.Maui.Controls.Xaml.IMarkupExtension

[<Microsoft.Maui.Controls.ContentProperty("Default")>]
[<Microsoft.Maui.Controls.Xaml.RequireService(new System.Type[] { typeof(Microsoft.Maui.Controls.Xaml.IProvideValueTarget), typeof(Microsoft.Maui.Controls.Xaml.IValueConverterProvider), typeof(Microsoft.Maui.Controls.Xaml.IXmlLineInfoProvider), typeof(Microsoft.Maui.Controls.Xaml.IConverterOptions) })>]
type OnPlatformExtension = class
    interface IMarkupExtension

[<Microsoft.Maui.Controls.ContentProperty("Default")>]
type OnPlatformExtension = class
    interface IMarkupExtension

Public Class OnPlatformExtension
Implements IMarkupExtension

Inheritance

Object

OnPlatformExtension

Attributes

ContentPropertyAttribute RequireServiceAttribute

Implements

IMarkupExtension

Remarks

The value is resolved by matching the Platform identifier (the DevicePlatform struct's ToString() value) against the per-platform values, so a custom backend whose platform string matches one of the named properties below (for example GTK) resolves correctly at runtime. The match is case-sensitive (ordinal, per DevicePlatform equality), so the identifier must match the property name's casing exactly — a backend reporting DevicePlatform.Create("gtk") (lowercase) does not match the GTK property and falls through to Default. Note that the compile-time optimization (SimplifyOnPlatformVisitor) currently recognizes only the -android/-ios/-macos/-maccatalyst target frameworks; every other target framework (including -windows and -tizen) and any custom backend falls back to runtime resolution.

Because a XAML markup extension maps each named argument to a CLR property, the inline {OnPlatform iOS=…, Android=…} form can only express the platforms exposed as properties here. To target an arbitrary custom platform (e.g. a backend reporting DevicePlatform.Create("Web")), use the element form, which accepts any platform string:

<OnPlatform x:TypeArguments="x:String">
    <On Platform="Web" Value="…" />
    <On Platform="iOS, Android" Value="…" />
</OnPlatform>