private void btnStart_Click(object sender, RoutedEventArgs e)
{
btnStart.IsEnabled = false;
btnStop.IsEnabled = true;
string ip = this.cbbIP.SelectedValue.ToString();
//MessageBox.Show(ip+":"+txtPort.Text+"已开始监听");
int p = int.Parse(txtPort.Text);
helper = new TCPHelper(IPAddress.Parse(ip), p);
helper.ExHandler += ShowMsg;
helper.StartListen(p);
ShowMsg(null, string.Format("{0}:{1}-->监听已开始", helper.IP, helper.port));
helper.AddTcpClientHandler += CreateClientTask;
Task.Run(() => helper.ListenClient());
}