Here we have a very simple application with 3 major parts: Index file with 1 localized text, A component with just a button that switches between 2 languages, and 3rd the MainLayout, which is used by the Index page and contains the LangBar component.

Let me share all the needed code:

We used localization only in a single text in the Index.razor:

 <h3>@Loc["stWelcome"]</h3>

Index.Razor (or Home.razor)

@page "/"
@inject IStringLocalizer<Index> Loc
@inject CultureState CultureState

<h3>@Loc["stWelcome"]</h3>

@code {
    protected override void OnInitialized()
    {
        CultureState.OnCultureChanged += HandleCultureChanged;
    }

    private void HandleCultureChanged()
    {
        StateHasChanged();
    }

    void Dispose()
    {
        CultureState.OnCultureChanged -= HandleCultureChanged;
    }
}

LangBar Usage (Our main component) : MainLayout.razor :

            <LangBar OnLanguageChanged="@HandleLanguageChange" />

MainLayout.razor Code:

@code 
{
     private void HandleLanguageChange()
     {
         //NavigationManager.NavigateTo(NavigationManager.Uri, true);
         StateHasChanged();
     }

     protected override void OnInitialized()
     {
         // Ensure initial UI update based on stored culture
         StateHasChanged();
     }    
}

CultureState class

    public string CurrentCulture { get; set; }

    public event Action OnCultureChanged;

    public void SetCulture(string culture)
    {
        CurrentCulture = culture;
        OnCultureChanged?.Invoke();
    }

Full code is on Github (Blazor 8.0 server side) :

Click here to check the code