ClaimsIdentity.FindFirst does not find claims

Question

User657329123 posted

Hi there,

I'm adding a claim like this in my controller

UserPrincipal principal = UserPrincipal.FindByIdentity(context, model.UserName);
firstName = principal.GivenName;
await UserManager.AddClaimAsync(user.Id, new Claim("first_name", firstName));

In my View, I'm trying to access first_name claim like this

@Html.ActionLink("Hello " + ((ClaimsIdentity)User.Identity).FindFirst("first_name").Value + "!", "Index", "Manage", routeValues: null, htmlAttributes: new { title = "Manage" })

but getting exception System.NullReferenceException: 'Object reference not set to an instance of an object.' In my view, I have added

@using Microsoft.AspNet.Identity;
@using System.Security.Claims;

What am I doing wrong?

Joe

Answer 1

User475983607 posted

joegreen2005

What am I doing wrong?

Claims are added to the auth token which lives in a cookie.  Claims are added to the auth cookie during sign in.   Your code is adding the claim to the user store not the principal in the current context.

More importantly you already have access to the GivenName property on the principal.  Why you adding the GivenName to a claim?

Answer 2

User657329123 posted

You are correct not sure why I'm adding GivenName to a Claim. I wrote a helper in view like this and I'm getting the GivenName now.

        @helper AccountName()
        {

                using (var context = new PrincipalContext(ContextType.Domain))
                {
                    var principal = UserPrincipal.FindByIdentity(context, User.Identity.Name);
                    @principal.GivenName
                }
        }


@Html.ActionLink("Hello " + AccountName() + "!", "Index", "Manage", routeValues: null, htmlAttributes: new { @title = "Manage", @class = "nav-link" })

I also removed the Claim that I was adding. But can someone tell me how do you read the ClaimValue from View using Razor. I need to get UserId somehow first and then get the ClaimValue to query AspNetUserClaims table.

Answer 3

User1724605321 posted

Hi joegreen :

But can someone tell me how do you read the ClaimValue from View using Razor. I need to get UserId somehow first and then get the ClaimValue to query AspNetUserClaims table.

Code below is for your reference :

@{
    var claimsIdentity = User.Identity as System.Security.Claims.ClaimsIdentity;

    if (claimsIdentity != null)
    {
        var c = claimsIdentity.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier);

        if (c != null)
        {
            <p>
                @c.Type.ToString();
                @c.Value.ToString();
            </p>
        }
    }
}

Best Regards,

Nan Yu