C# socket program auto close -

when use program socket range of ip address, it's closed time without message. program ends. how can fix problem? (it console project)

public static void main(string[] args) {     task[] tasks = new task[200];     (int = 0; < 200; i++)     {         tasks[i] = task.factory.startnew(() => runningthread());     }     task.waitall(tasks);     console.writeline("finish...");     console.readkey();     //..... }  public bool socketip(string ip, int port) {     autoresetevent arevent = new autoresetevent(false);     socket socket = new socket(addressfamily.internetwork, sockettype.stream, protocoltype.tcp);      if (socket != null)     {         socket.bind(new ipendpoint(ipaddress.any, 0));         socket.beginconnect(new ipendpoint(ipaddress.parse(ip), port), callback, new arraylist() { socket, arevent});         arevent.waitone(waittime);         if (rv)             socket.shutdown(socketshutdown.both);         socket.close();         socket = null;     }     return rv; }   void callback(iasyncresult ar) {     arraylist list = (arraylist)ar.asyncstate;     socket socket = (socket)list[0];      autoresetevent arevent = (autoresetevent)list[1];      if (ar.iscompleted && socket.connected)         rv = true;     arevent.set(); } 

the way code looks should stop @ console.readkey(). maybe there crash unhandled in program. try putting try catch around complete main function en debug on exception ex. mean this:

public static void main(string[] args) { try{     task[] tasks = new task[200];     (int = 0; < 200; i++)     {         tasks[i] = task.factory.startnew(() => runningthread());     }     task.waitall(tasks);     console.writeline("finish...");     console.readkey();     //..... } catch(exception ex) {  console.writeline(ex.message); <<<--(break point here) } }