In last week’s post, Server-Side Blazor with Authentication, we covered creating a Server-Side Blazor application with Authentication and then used the attribute to not allow the user to view the Fetch data page if they weren’t logged in.
While the authorize attribute does keep the user from viewing the contents of the page it still allows the user access to the nav menu item for the page they aren’t authorized to access. This is going to be a quick post showing how the AuthorizedView component can be used to hide any content that a user should be logged in to see (or be in a specific role).
Hide a Nav Menu Item
In the Pages/Shared directory open the NavMenu.razor file which is the file where the nav menu is defined. The following code is the code that renders the Fetch data menu item which is the section we want to hide if the user isn’t logged in.
<li class="nav-item px-3"> <NavLink class="nav-link" href="fetchdata"> <span class="oi oi-list-rich" aria-hidden="true"></span> Fetch data </NavLink> </li>
To hide menu item we wrap the list item in the AuthorizeView component.
<AuthorizeView> <li class="nav-item px-3"> <NavLink class="nav-link" href="fetchdata"> <span class="oi oi-list-rich" aria-hidden="true"></span> Fetch data </NavLink> </li> </AuthorizeView>
Do note that you should still use the Authorize attribute on the page that should require authorization and not depend on the menu item being hidden keeping users from finding the page.
While the Authorize attribute is still very useful I’m sure that the AuthorizeView will be getting a lot of use in Blazor apps. AuthrozieView has the advantage of not being limited to page component.
Also, note that AuthorizeView also supports roles and policies. Make sure and check out the official AuthorizeView component docs for more details. If interested the code for the component is on GitHub.