You can use JSON to send multiple data values in one string. In the following code example, JSON is used to create a set of name-value pairs to represent latitude and longitude coordinates.

// Create the JSON string to send.
var latLonStr = "{'lat':'47.7575', 'lon':'-122.24278'}";

// Use the eval function to convert the string back into an object.
// This would typically be used on the receiving side.
var latLonObj = eval('(' + latLonStr + ')');

// Test it out using an alert.
alert('latitude: ' + latLonObj.lat + ', longitude: ' + latLonObj.lon);

For more information, see the JSON Web site.

The following procedures walk you through the individual steps of implementing messaging extensions.

1. Create the ApplicationMessageFactory object constructor.

   This object serializes and deserializes your messaging extension.

   _myMessageFactory = function _myMessageFactory(_user) {
       _myMessageFactory.constructBase(this, [ _user ]);
   }

2. Create the serialize and deserialize functions.

   In this example, the serialize method returns a string value, but the return value varies depending on the implementation. The value returned by serialize is what ultimately gets sent.

   _myMessageFactory.prototype = {
      
       deserialize: function deserialize(sender, id, content) {
           if (id == _myApplicationMessage.Id)
           {
               return new _myApplicationMessage(content);
           }
           else
           {
               return null;
           }
       },
      
       serialize: function serialize(message) {
           return (message).get_myString();
       }
   }

1. Create the ApplicationMessage object constructor.

   In this example, a custom string value is added.

   _myApplicationMessage = function _myApplicationMessage(str) {
       _myApplicationMessage.constructBase(this);
       this.myString = str;
   }

2. Add methods to the ApplicationMessage object.

   The get_id() method is always required. In this example, an additional method called get_myString() has been added to handle the custom string value for this class.

   _myApplicationMessage.prototype = {
       myString: null,
      
       get_id: function get_id() {
           return _myApplicationMessage.Id;
       },
      
       get_myString: function get_myString() {
           return this.myString;
       }
   }

3. Assign a value to the Id property for the object.

   _myApplicationMessage.Id = 'msgid';

• Add the following code to the end of your OnSignInCompleted function.

  if (!_user.get_messageFactory()) 
  {
      _user.set_messageFactory(new _myMessageFactory(_user));
      if (!_user.get_messageFactory().isRegistered(_myApplicationMessage.Id)) 
      {
          _user.get_messageFactory().register(_myApplicationMessage.Id);
      }
  }

• In this example, the message function checks to see if the current conversation supports the ID of the message. If it does, the message is sent.

  function sendCustomMsg()
  {
      if (_conv.supportsApplicationMessageType(_myApplicationMessage.Id))
      {
          if (_user) 
          {
          var message = new _myApplicationMessage(customMessageMenu.selectedIndex.toString());
          _conv.sendMessage(message, null);
          }
      }
  }

• The following function uses a switch statement to determine the MessageType of an incoming message, and then takes the appropriate action.

  function recvMsg(sender, e)
  {
      switch (e.get_message().get_type()) 
      {
          case Microsoft.Live.Messenger.MessageType.applicationMessage:
              var customMessage = e.get_message();
              if (message.get_id() == _myApplicationMessage.Id) 
              {
                  // Add code to handle the message content here.
              }
              break;
          case Microsoft.Live.Messenger.MessageType.textMessage:
              var message = e.get_message();
              // Add code to handle the message content here.
              break;        
          default:
              break;
      }
  }

Concepts