Get Current User in a Blazor component

Question

I'm starting a new site with Blazor and Windows Authentication and need to identify the current user viewing the page/component.

For a Razor Page, the current user name can be accessed with Context.User.Identity.Name, but that doesn't seem to work in a Blazor component. I've tried injecting HttpContext into the component but the Context is null at runtime.

As a bonus, I will eventually want to incorporate this into Startup.cs so I only need to get the username once and can leverage a corporate user class (with EF Core) for my applications. Answers tailored to that use case would also be appreciated.

Answer 1

There are three possibilities for getting the user in a component (a page is a component):

1. Inject IHttpContextAccessor and from it access HttpContext and then User; need to register IHttpContextAccessor in Startup.ConfigureServices, normally using AddHttpContextAccessor
2. Inject a AuthenticationStateProvider property, call GetAuthenticationStateAsync and get User from it
3. Wrap your component in a <CascadingAuthenticationState> component, declare a Task<AuthenticationState> property and call it to get the User (similar to #2)

See more here: https://docs.microsoft.com/en-us/aspnet/core/security/blazor.