问如何为多个用户角色构建.NET Core项目？

EN

@if (!SignInManager.IsSignedIn(User))
{
    <header>
        <nav class="navbar navbar-expand-sm navbar-toggleable-sm navbar-light bg-white border-bottom box-shadow mb-3">
            <div class="container">
                <a class="navbar-brand" asp-area="" asp-controller="Home" asp-action="Index">WebApp</a>
                <button class="navbar-toggler" type="button" data-toggle="collapse" data-target=".navbar-collapse" aria-controls="navbarSupportedContent"
                        aria-expanded="false" aria-label="Toggle navigation">
                    <span class="navbar-toggler-icon"></span>
                </button>
                <div class="navbar-collapse collapse d-sm-inline-flex flex-sm-row-reverse">
                    <partial name="_LoginPartial" />
                    <ul class="navbar-nav flex-grow-1">
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Index">Home</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Privacy">Privacy</a>
                        </li>
                    </ul>
                </div>
            </div>
        </nav>
    </header>
}
else
{
    if (User.IsInRole("manager"))
    {
        //navigation bar for manager

        //html content here
        //...

        <a class="nav-link text-dark" asp-area="Manager" asp-controller="controller_name_here" asp-action="action_name_here">Admin Home</a>
    }
    else if (User.IsInRole("employee"))
    {
        //navigation bar for employee
    }
    else
    {
        //navigation bar for employee
    }