/// <summary>
/// 获取群组所有成员用户Id集合(用于推送动态）
/// </summary>
/// <param name="groupId">群组Id</param>
/// <returns></returns>
public IEnumerable <long> GetUserIdsOfGroup(long groupId)
{
GroupEntity group = groupRepository.Get(groupId);
if (group == null)
{
return(new List <long>());
}
//不必缓存
IEnumerable <long> userIds = groupMemberRepository.GetUserIdsOfGroup(groupId);
var list = userIds.ToList();
list.Add(group.UserId);
return(list);
}