OnLocationChanged not fired in .NET 8 Preview 7 Blazor Web App

[KeldJ]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

In the code below (https://github.com/KeldJ/BlazorApp9) navigation to all urls are Catched and should fire OnLocationChanged which increases ID.

@page "/{*pageRoute}"
@Attribute [RenderModeServer(false)]
@Inject NavigationManager NavigationManager
@implements IDisposable
Home

@ID.ToString()


PageRoute: @PageRoute

@code {

private int ID { get; set; } = 0;

[Parameter]
public string? PageRoute { get; set; }

protected override async Task OnInitializedAsync()
{
	await Task.Delay(1);
	NavigationManager.LocationChanged += OnLocationChanged;
}

private async void OnLocationChanged(object? sender, LocationChangedEventArgs e)
{
	ID++;
	await InvokeAsync(StateHasChanged);
}

public void Dispose()
{
	NavigationManager.LocationChanged -= OnLocationChanged;
}

}

Expected Behavior

OnLocationChanged should be fired and ID should be increased.

Steps To Reproduce

https://github.com/KeldJ/BlazorApp9

Exceptions (if any)

No response

.NET Version

8.0.100-preview.7.23376.3

Anything else?

No response

[bub-bl]

When you set a new uri from the address bar, you lose the state of your app. This is the reason why the LocationChanged event is never triggered and the Id property stay at 0. If you add the following code, you can see, the Id property is now updated when you navigate from the NavigateTo() function.

@page "/{*pageRoute}"
@attribute [RenderModeServer(false)]
@inject NavigationManager NavigationManager
@implements IDisposable

@Id.ToString()
<br/>
PageRoute: @PageRoute

<button @onclick="@(() => NavigateTo("/counter1/1"))">Counter 1</button>
<button @onclick="@(() => NavigateTo("/counter1/2"))">Counter 2</button>
<button @onclick="@(() => NavigateTo("/counter1/3"))">Counter 3</button>

@code {

    private int Id { get; set; }

    [Parameter]
    public string? PageRoute { get; set; }

    protected override async Task OnInitializedAsync()
    {
        await Task.Delay(1);
        NavigationManager.LocationChanged += OnLocationChanged;
    }

    private async void OnLocationChanged(object? sender, LocationChangedEventArgs e)
    {
        Id++;
        await InvokeAsync(StateHasChanged);
    }

    private void NavigateTo(string nav)
    {
        NavigationManager.NavigateTo(nav);
    }
    
    public void Dispose()
    {
        NavigationManager.LocationChanged -= OnLocationChanged;
    }

}

[KeldJ]

in .NET 8 Preview 6 the OnLocationChanged get fired using regular a href links like the attached Git Project.

The project on https://cms1.l-mediehus.dk/ (Early alfa version) are built on Preview 6 and the links are catched by OnLocationChanged as desired

[bub-bl]

It seems to be a bug. But yes, NavigationManager seems to have a problem with LocationChanged. It's never triggered. I've tried putting them in App.razor and MainLayout.razor but I always get the same result. LocationChanged is only triggered in the page where it was registered and when we use NavigationManager.NavigateTo() to change the location.

We also get the same result with RenderModeWebAssembly.

[mkArtakMSFT]

Related and will be partially addressed as part of #48766

[surayya-MS]

Done in this PR #51279