I use the default Blazor NavMenu component and want to disable it when the user opens a window. In my app the input data from the user on the opened page has to be validated first before the user is allowed to click another item on the NavMenu.

I use the default Blazor NavMenu component and want to disable it when the user opens a window. In my app the input data from the user on the opened page has to be validated first before the user is allowed to click another item on the NavMenu.

• asp-core
• blazor

2 Answers 2

Wrap the links you only want shown when authorized in AuthorizeView.

Here's a demo:

<AuthorizeView>
    <Authorized>
        <p>Hello, @context.User.Identity?.Name!</p>
        <p><button @onclick="HandleClick">Authorized Only Button</button></p>
    </Authorized>
    <NotAuthorized>
        <p>You're not authorized.</p>
    </NotAuthorized>
</AuthorizeView>

The Microsoft Docs article is here: https://learn.microsoft/en-us/aspnet/core/blazor/security/?view=aspnetcore-9.0&tabs=visual-studio#authorizeview-component

As MrC aka Shaun Curtis said, you can add AuthorizeView in the NavMenu component.

In the AuthorizedView, you can add NavLink both in the Authorized and NotAuthorized, in the NotAuthorized area, disable the NavLink using BootStrap Pointer events(add pe-none class, you can also disable the link by adding custom CSS style.)

    <AuthorizeView>
        <Authorized>
            <div class="nav-item px-3">
                <NavLink class="nav-link" href="auth">
                    <span class="bi bi-lock-nav-menu" aria-hidden="true"></span> Auth Required
                </NavLink>
            </div>
        </Authorized>
        <NotAuthorized>
            <div class="nav-item px-3">
                <NavLink class="nav-link pe-none" href="auth" style="">
                    <span class="bi bi-lock-nav-menu" aria-hidden="true"></span> AuthRequired(Disabled)
                </NavLink>
            </div>
        </NotAuthorized>
    </AuthorizeView>

Besides, you can also use AuthenticationStateProvider in NavMenu, based on the user's IsAuthenticated status to add NavLink, add the following code in the NavMenu component:

    @inject AuthenticationStateProvider AuthenticationStateProvider
    @using Microsoft.AspNetCore.Components.Authorization

    @code {
        private string? currentUrl;

        private bool isAuthenticated; 
        protected override async Task OnInitializedAsync()
        {
            currentUrl = NavigationManager.ToBaseRelativePath(NavigationManager.Uri);
            NavigationManager.LocationChanged += OnLocationChanged;

            var authState = await AuthenticationStateProvider.GetAuthenticationStateAsync();
            isAuthenticated = authState.User.Identity?.IsAuthenticated ?? false;
        }

Then use the following code to add NavLink:

    <div class="nav-item px-3">
        @if (isAuthenticated)
        {
            <NavLink class="nav-link" href="weather">
                <span class="bi bi-list-nested-nav-menu" aria-hidden="true"></span> Weather
            </NavLink>
        }
        else
        {
            <NavLink class="nav-link  pe-none" href="weather">
                <span class="bi bi-list-nested-nav-menu" aria-hidden="true"></span> Weather(Disabled)
            </NavLink>
        } 
    </div>

The result as below:

Before login, the NavLink is disabled

Once you have successfully logged in, NavLink is clickable, and you can navigate to the relevant page:

The NavMenu component like this:

@implements IDisposable

@inject NavigationManager NavigationManager
        @inject AuthenticationStateProvider AuthenticationStateProvider
        @using Microsoft.AspNetCore.Components.Authorization
<div class="top-row ps-3 navbar navbar-dark">
    <div class="container-fluid">
        <a class="navbar-brand" href="">BlazorServerIdentity</a>
    </div>
</div>

<input type="checkbox" title="Navigation menu" class="navbar-toggler" />

<div class="nav-scrollable" onclick="document.querySelector('.navbar-toggler').click()">
    <nav class="nav flex-column">
        <div class="nav-item px-3">
            <NavLink class="nav-link" href="" Match="NavLinkMatch.All">
                <span class="bi bi-house-door-fill-nav-menu" aria-hidden="true"></span> Home
            </NavLink>
        </div>

        <div class="nav-item px-3">
            <NavLink class="nav-link" href="counter">
                <span class="bi bi-plus-square-fill-nav-menu" aria-hidden="true"></span> Counter
            </NavLink>
        </div>

        <div class="nav-item px-3">
            @if (isAuthenticated)
            {
                <NavLink class="nav-link" href="weather">
                    <span class="bi bi-list-nested-nav-menu" aria-hidden="true"></span> Weather
                </NavLink>
            }
            else
            {
                <NavLink class="nav-link  pe-none" href="weather">
                    <span class="bi bi-list-nested-nav-menu" aria-hidden="true"></span> Weather(Disabled)
                </NavLink>
            } 
        </div>

        <AuthorizeView>
            <Authorized>
                <div class="nav-item px-3">
                    <NavLink class="nav-link" href="auth">
                        <span class="bi bi-lock-nav-menu" aria-hidden="true"></span> Auth Required
                    </NavLink>
                </div>
            </Authorized>
            <NotAuthorized>
                <div class="nav-item px-3">
                    <NavLink class="nav-link pe-none" href="auth" style="">
                        <span class="bi bi-lock-nav-menu" aria-hidden="true"></span> AuthRequired(Disabled)
                    </NavLink>
                </div>
            </NotAuthorized>
        </AuthorizeView>

        <AuthorizeView>
            <Authorized>
                <div class="nav-item px-3">
                    <NavLink class="nav-link" href="Account/Manage">
                        <span class="bi bi-person-fill-nav-menu" aria-hidden="true"></span> @context.User.Identity?.Name
                    </NavLink>
                </div>
                <div class="nav-item px-3">
                    <form action="Account/Logout" method="post">
                        <AntiferyToken />
                        <input type="hidden" name="ReturnUrl" value="@currentUrl" />
                        <button type="submit" class="nav-link">
                            <span class="bi bi-arrow-bar-left-nav-menu" aria-hidden="true"></span> Logout
                        </button>
                    </form>
                </div>
            </Authorized>
            <NotAuthorized>
                <div class="nav-item px-3">
                    <NavLink class="nav-link" href="Account/Register">
                        <span class="bi bi-person-nav-menu" aria-hidden="true"></span> Register
                    </NavLink>
                </div>
                <div class="nav-item px-3">
                    <NavLink class="nav-link" href="Account/Login">
                        <span class="bi bi-person-badge-nav-menu" aria-hidden="true"></span> Login
                    </NavLink>
                </div>
            </NotAuthorized>
        </AuthorizeView>
    </nav>
</div>

@code {
    private string? currentUrl;

    private bool isAuthenticated; 
    protected override async Task OnInitializedAsync()
    {
        currentUrl = NavigationManager.ToBaseRelativePath(NavigationManager.Uri);
        NavigationManager.LocationChanged += OnLocationChanged;

        var authState = await AuthenticationStateProvider.GetAuthenticationStateAsync();
        isAuthenticated = authState.User.Identity?.IsAuthenticated ?? false;
    }

    private void OnLocationChanged(object? sender, LocationChangedEventArgs e)
    {
        currentUrl = NavigationManager.ToBaseRelativePath(e.Location);
        StateHasChanged();
    }

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