title: Messaging Center is not trigger on PageModel Xamarin Forms
body: <p>I have an ZXing scanner page,I want to get the scan data from ScanPageModel to MyPageModel</p>
  
  <p>I am opening scan page From MyPageModel</p>
  
  <pre><code>public Command ScanCode
          {
              get
              {
                  return new Command(async () =&gt;
                  {
                      MessagingCenter.Subscribe&lt;MyPageModel&gt;(this, "ScanText", (value) =&gt;
                      {
  
                      });
                      await CoreMethods.PushPageModel&lt;ScanPageModel&gt;();
  
                  });
              }
          }
  </code></pre>
  
  <p>after getting the scan result from ScanPageModel send the messaging center data</p>
  
  <pre><code> private void ScanResultAction(object obj)
          {
              // Prevent multiple event triggers from triggering the navigation multiple times
              if (NavigatingAway)
                  return;
  
              NavigatingAway = true;          
              var result = obj as ZXing.Result;
              var format = result?.BarcodeFormat.ToString() ?? string.Empty;
              var value = result?.Text ?? string.Empty;
              // Navigate to a page based on value
              SampleListData sa = new SampleListData();
              sa.Name = value;
              Device.BeginInvokeOnMainThread(async () =&gt;
              {
                  MessagingCenter.Send&lt;ScanPageModel, string&gt;(this, "ScanText", result.Text);
                  await CoreMethods.PopPageModel();
              });
          } 
  </code></pre>
  
  <p>But my messaging center not called after sending data from ScanPageModel
  Here is the Subscribe method for receiving Scan Code</p>
  
  <pre><code>public MyPageModel()
          {
              MessagingCenter.Subscribe&lt;SampleListData&gt;(this, "ScanText", (value) =&gt;
              {
  
              });
          }
  </code></pre>
  
  <p>I also tried to place this subscribe inside </p>
  
  <pre><code> public override void Init(object initData)
          {
              MessagingCenter.Subscribe&lt;SampleListData&gt;(this, "ScanText", (value) =&gt;
                  {
  
                  });
          }
  </code></pre>
  
  <p>But its also not working
  So How to solve this?</p>