title: How to stop messaging center to stop subscribe multiple time in Xamarin.Forms?
body: <p>I am creating an application and in that it need to send argument to the other page and send argument using the Messagingcenter when I send using MessagingCenter it call more than one time.</p>
  
  <p>If I am using unscribe than in next time it is not receive next time.</p>
  
  <pre><code>MessagingCenter.Send(this, "Invoke", "Invokedtrue");
  
  MessagingCenter.Subscribe&lt;MyPage, string&gt;(this, "Invoke", async (sender, arg) =&gt;
  {
      await Process(arg);
  });
  MessagingCenter.Unsubscribe&lt;MyPage&gt;(this,"Invoke");
  
  
  **ListPage**
  
      private void ViewCell_Tapped(object sender, EventArgs e)
      {
          try
          {
              MessagingCenter.Send(this, "Invoke", "Invokedtrue");
          }
          catch (Exception ex)
          {
              Debug.Write(ex);
          }
      }
  
  **Detail Page**
  
      MessagingCenter.Subscribe&lt;ListPage, string&gt;(this, "Invoke", async (sender, arg) =&gt;
      {
          await Process(arg);
      });
  
      private async Task Process(string arg)
      {
          //Here is api call to view detail of particular record
  
          //Here I unsubscribe the MessagingCenter.
          MessagingCenter.Unsubscribe&lt;ListPage&gt;(this,"Invoke");
      }
  </code></pre>
  
  <p>I want to send only one time using subscribe and send only one time.</p>
  
  <p>Can anyone look into this and suggest me what should I have to do in that?</p>