/// <summary>
/// Wrapper to cache the membership provider key (id) from the request cache
/// </summary>
/// <param name="key">
/// The key.
/// </param>
/// <returns>
/// The <see cref="string"/>.
/// </returns>
protected string MembershipProviderKey(Guid key)
{
return((string)Cache.RequestCache.GetCacheItem(CacheKeys.CustomerMembershipProviderKey(key), this.GetMembershipProviderKey));
}