/// <summary>
/// 从某个角色列表中轮循获取一个用户，在线的用户优先。
/// </summary>
/// <param name="roleCode">角色编号</param>
/// <param name="userId">当前用户主键</param>
/// <param name="cacheHours">缓存小时数</param>
/// <returns>用户主键</returns>
public string GetRandomUserId(IDbHelper dbHelper, string roleCode, string userId, int cacheHours = 4)
{
string result = null;
// 检查缓存里，是否有这个用户的对应客服的主键？若没有进行分配
System.Web.Caching.Cache cache = HttpRuntime.Cache;
if (!string.IsNullOrEmpty(userId))
{
if (cache != null && cache[userId] == null)
{
var manager = new BaseUserManager(dbHelper);
result = manager.GetRandomUserId("Base", roleCode);
cache.Add(userId, result, null, DateTime.Now.AddHours(cacheHours), TimeSpan.Zero, CacheItemPriority.Normal, null);
}
result = cache[userId] as string;
}
return(result);
}