如何从ASP.NET Web API方法中查找声明的内容？

public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
    {
        var userManager = context.OwinContext.GetUserManager<ApplicationUserManager>();
        ApplicationUser user = await userManager.FindAsync(context.UserName,context.Password);
        if (user == null)
        {
            context.SetError("invalid_grant","The user name or password is incorrect.");
            return;
        }
        ClaimsIdentity oAuthIdentity = await user.GenerateUserIdentityAsync(userManager,OAuthDefaults.AuthenticationType);
        ClaimsIdentity cookiesIdentity = await user.GenerateUserIdentityAsync(userManager,CookieAuthenticationDefaults.AuthenticationType);
        AuthenticationProperties properties = CreateProperties(
            user.UserName,oAuthIdentity,user.FirstName,user.LastName,user.Organization);
        AuthenticationTicket ticket = new AuthenticationTicket(oAuthIdentity,properties);
        context.Validated(ticket);
        context.Request.Context.Authentication.SignIn(cookiesIdentity);
    }

这是CreateProperites方法,然后添加了角色声明：

public static AuthenticationProperties CreateProperties(
        string userName,ClaimsIdentity oAuthIdentity,string firstName,string lastName,int organization)
    {

        IDictionary<string,string> data = new Dictionary<string,string>
            {
                { "userName",userName},{ "firstName",firstName},{ "lastName",lastName},{ "organization",organization.ToString()},{ "roles",string.Join(":",oAuthIdentity.Claims.Where(c=> c.Type == ClaimTypes.Role).Select(c => c.Value).ToArray())}

            };
        return new AuthenticationProperties(data);
    }

在我的客户端上,我发出一个令牌请求,然后像这样收到它：

this.$http({
        method: 'POST',url: '/Token',headers: {
            'Content-Type': 'application/x-www-form-urlencoded',},data: 'grant_type=password&username=' + encodeURIComponent(userName) + '&password=' + encodeURIComponent(password),})
        .success((data: any,status,headers,cfg) => {
            self.data.roles = data.roles;

我可以看到self.data.roles正确填充了角色.现在回到服务器上我想查看角色声明的内容.有人可以通过告诉我如何做到这一点来帮忙吗？我知道我可以在一个方法中执行以下操作：

[HttpGet]
    [Route("Retrieve")]
    public async Task<IHttpActionResult> Retrieve()
    {

        var x = User;

x获取的值

System.Security.Claims.ClaimsPrinciple and 
System.Security.Claims.ClaimsIdentity

但在x内我找不到索赔本身的信息.

请注意,我之前尝试过在SO上发布的建议：

var identity = (ClaimsIdentity)User.Identity;
        IEnumerable<Claim> claims = identity.Claims;

        // The following line returns null
        var roles = identity.Claims.Where(r => r.Type == "roles").FirstOrDefault();

但我仍然无法在索赔内找到与角色声明相关的信息.我知道它必须在那里,因为它到达客户端.

请注意我正在寻找具体的“角色”声明.没有任何系统生成的声明.但是我试图添加自己的那个包含角色的连接列表.