limanapp/LiMan.UI/Components/LoginDisplay.razor

@using Microsoft.AspNetCore.Components.Authorization

@inject AuthenticationStateProvider AuthenticationStateProvider

<AuthorizeView>
    <Authorized>
        <div class="input-group text-truncate">
            <div class="input-group-prepend">
                <a title="LogOut" href="Identity/Account/LogOut" class="btn btn-sm btn-danger"><i class="fas fa-sign-out-alt"></i></a>
            </div>
            <a title="Gestione account @userName" href="Identity/Account/Manage" class="btn btn-sm btn-outline-dark mx-0 px-1">
                <div class="d-none d-sm-block">
                    <i class="fas fa-user-alt"></i> @StringLim(userName, 30)
                </div>
                <div class="d-block d-sm-none">
                    <i class="fas fa-user-alt"></i> @StringLim(userName, 15)
                </div>
            </a>
        </div>
    </Authorized>
    <NotAuthorized>
        <div class="input-group">
            <div class="input-group-prepend">
                <a title="LogIn" href="Identity/Account/LogIn" class="btn btn-sm btn-success"><i class="fas fa-sign-in-alt"></i></a>
            </div>
            <div class="form-control form-control-sm">
                <i class="fas fa-user-alt"></i>&nbsp;@userName
            </div>
        </div>
    </NotAuthorized>
</AuthorizeView>

@code{

    private string userName = "";
    protected override async Task OnInitializedAsync()
    {
        await forceReload();
    }
    private async Task forceReload()
    {

        var authState = await AuthenticationStateProvider.GetAuthenticationStateAsync();
        var user = authState.User;

        if (user.Identity.IsAuthenticated)
        {
            userName = $"{user.Identity.Name}";
        }
        else
        {
            userName = "Non Autenticato";
        }
    }

    protected string StringLim(string original, int maxLen)
    {
        return original.Length <= maxLen ? original : $"{original.Substring(0, maxLen - 3)}...";
    }

}