如何使用索赔

我有一个使用Asp的Web API 2.1。NET-Identity 2.0(代码优先)用于身份验证。

我的问题是更新/删除用户声明，AuthenticationType是"承载者"。我有一个索赔名为"instance"，我想更新它。我有一个authprovider派生自OAuthAuthorizationServerProvider我覆盖了GrantResourceOwnerCredentials所以它看起来像这样:

var user = await userManager.FindAsync(context.UserName, context.Password);
var identity = new ClaimsIdentity(new[] 
    { 
        new Claim(ClaimTypes.Name, user.UserName) 
    }, 
    context.Options.AuthenticationType, 
    ClaimTypes.Name, 
    ClaimTypes.Role);
identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, user.Id));
identity.AddClaim(new Claim(ClaimTypes.Instances, "test"));
var ticket = new AuthenticationTicket(identity, new AuthenticationProperties());
context.Validated(ticket);

然后在我的UserController我有一个函数来更新索赔"instance"。

var user = (ClaimsIdentity)User.Identity;
var insClaim = user.Claims.Single(x => x.Type == ClaimTypes.Instances);
user.RemoveClaim(insClaim);
user.AddClaim(new Claim(ClaimTypes.Instances, "TEST 123"));
var ctx = Request.GetOwinContext();
var authCtx = await ctx.Authentication.AuthenticateAsync(user.AuthenticationType);
if (authCtx != null)
{
    ctx.Authentication.SignOut(user.AuthenticationType);
    ctx.Authentication.AuthenticationResponseGrant = new AuthenticationResponseGrant(user, authCtx.Properties);
    ctx.Authentication.SignIn(user);
}
return Ok(new { });

但是下一次我试图从用户那里获得"实例"时，它仍然具有值"test"。我错过了什么?