使用Web服务将客户端标记为脱机的最佳方法

Question

Currently I'm working with a Web-Service where Client's Continually should update Data . So the WebService has a List<Client> clients; where it stores Connected Client's :

[WebMethod]
public string Connect(Size desktopsize)
{
  Client clienti = new Client();
  clienti.ID = "Client_" + Counter.ToString();
  clienti.Desktopsize = desktopsize;
  clienti.Lastupdate = DateTime.Now;
  Counter++;
  clients.Add(clienti);
  return clienti.ID;
}

so every client has an ID ,and continue Updating it's Data's. I need to mark a Client Offline ,than when the Last Update of a specific Client was 1 minute ago .(Im also updating the UpdateTime every time when a value is changed like :

public bool SingleClick
{
  get
  {
    bool tmpBolean = singleclick;
    singleclick = false;
    return tmpBolean;
  }
  set
  {
    this.lastupdate = DateTime.Now;
    singleclick = value;
  }
}

First i used to create a Thread at Client

private void CheckOnlinestate()
{
  while (isRunning)
  {
    TimeSpan ts = DateTime.Now - lastupdate;
    if (ts.TotalMinutes >= 1)
    {
      isRunning = false;
      this.Dispose();
    }
  }
} 

than at WebService a thread which monitor's if Client should remove from list:

public void CheckClients()
{
  while (true)
  {
    foreach (Client c in clients)
    {
      if (c.ShouldDispose)
      {
        clients.Remove(c);
      }
    }
    Thread.Sleep(200);
  }
}

So the issue is ,how to use this method into a Thread Correctly ,should i Create and Start the thread at WebService Constructor ,or there is a better way to do that. I cant imagine the best way how to remove a specific Client from List<Client> clients;

Answer 1

You can use System.Web.HttpRuntime.Cache class instead of implementing your own.

There are some other problems with your code. Accesses to Counter and clients are uncontrolled which are shared among threads. You should use some sync. mechanism such as lock while accessing these objects ( You can forget my comment about clients if you already declared it as ConcurrentDictionary )