NavigationAware

Apply [NavigationAware] to a partial class to emit INavigationAware members and optional OnNavigatedToCore / IsNavigationTargetCore / OnNavigatedFromCore hooks.

The generator runs when the compilation references a regions API:

Prism	Namespace
9+	Prism.Navigation.Regions
8	Prism.Regions (from Prism.Wpf, Prism.Avalonia, etc.)

Usage

using Prism.Mvvm;
using Prism.Navigation.Regions; // or Prism.Regions on Prism 8
using Prism.SourceGenerators;

[NavigationAware]
public partial class DashboardViewModel : BindableBase
{
    partial void OnNavigatedToCore(NavigationContext navigationContext)
    {
        // Called when the view enters the region.
    }
}

Override navigation reuse with private partial bool IsNavigationTargetCore(...) when the default true is not enough.

Generated members

• OnNavigatedTo → calls OnNavigatedToCore
• IsNavigationTarget → calls IsNavigationTargetCore (default true in generated partial)
• OnNavigatedFrom → calls OnNavigatedFromCore

[FromNavigationParameter]

Apply [FromNavigationParameter] to an [ObservableProperty] field or partial property to read a typed value from NavigationContext.Parameters via TryGetValue<T> and assign it through the property setter before OnNavigatedToCore is invoked.

[NavigationAware]
public partial class DashboardViewModel : BindableBase
{
    [FromNavigationParameter("userId")]
    [ObservableProperty]
    public partial int UserId { get; set; }

    [FromNavigationParameter]  // key defaults to "UserName"
    [ObservableProperty]
    public partial string UserName { get; set; }
}

If the parameter is absent, the property retains its initial value. The key defaults to the property name when not specified.

Diagnostics

ID	When
PSG0007	Class is not partial — use the Add partial code fix
PSG7006	Attribute applied to a non-field/property member
PSG7007	Member lacks [ObservableProperty]
PSG7008	Key is empty

Related

• NavigateCommand
• Container registration — [RegisterForNavigation]
• Samples