Check if a user belongs to an AD group

gistfile1.cs

using System.DirectoryServices.AccountManagement;

try
{
	string adGroupName = "ACTIVE_DIR_GROUP_NAME";
        string userAccount = "USER_ACCOUNT_NAME"
	using (System.Web.Hosting.HostingEnvironment.Impersonate())
	{
		PrincipalContext ctx = new PrincipalContext(ContextType.Domain);
		GroupPrincipal permissionGroup = GroupPrincipal.FindByIdentity(ctx, adGroupName);
		UserPrincipal userPrincipal = UserPrincipal.FindByIdentity(ctx, userAccount);
		return userPrincipal.IsMemberOf(permissionGroup);	   
	}
}
catch (Exception e)
{
	return false;
}