如何检查用户是否为组成员

 public static class Security
{
    public static bool IsInGroup(this ClaimsPrincipal User, string GroupName)
    {
        var groups = new List<string>();

        var wi = (WindowsIdentity)User.Identity;
        if (wi.Groups != null)
        {
            foreach (var group in wi.Groups)
            {
                try
                {
                    groups.Add(group.Translate(typeof(NTAccount)).ToString());
                }
                catch (Exception)
                {
                    // ignored
                }
            }
            return groups.Contains(GroupName);
        }
        return false;
    }
}

 if (User.IsInGroup("GroupName"))
 {

 }