MVC 5 Owin Facebook Auth results in Null Reference Exception

Question

I\'m trying to setup integrated OWIN Facebook authentication in a new MVC 5 project in Visual Studio 2013. I have configured apps and keys as per this tutorial:

http

Answer 1

Hongye Sun did all the heavy lifting in his answer above.

Here's some code that can be added to your controller class and be called in place of the troublesome AuthenticationManager.GetExternalLoginInfoAsync().

private async Task AuthenticationManager_GetExternalLoginInfoAsync_Workaround()
{
    ExternalLoginInfo loginInfo = null;

    var result = await AuthenticationManager.AuthenticateAsync(DefaultAuthenticationTypes.ExternalCookie);

    if (result != null && result.Identity != null)
    {
        var idClaim = result.Identity.FindFirst(ClaimTypes.NameIdentifier);
        if (idClaim != null)
        {
            loginInfo = new ExternalLoginInfo()
            {
                DefaultUserName = result.Identity.Name == null ? "" : result.Identity.Name.Replace(" ", ""),
                Login = new UserLoginInfo(idClaim.Issuer, idClaim.Value)
            };
        }
    }
    return loginInfo;
}