void Connected()
 {
     _ViewModelBase.Dispather.InvokeIfRequired(delegate()
     {
         CloseWindowConnecting();
         windowJoin = new Window_Join();
         windowJoin.DataContext = this.Context;
         windowJoin.Owner = this;
         bool? r = windowJoin.ShowDialog();
     }, System.Windows.Threading.DispatcherPriority.Normal);
 }
 void CloseWindowJoin()
 {
     if (windowJoin != null)
     {
         try
         {
             windowJoin.Close();
             windowJoin = null;
         }
         catch { }
     }
 }