May 18, 2002 - Using the set and get Member Functions

Yehuda Shiran May 18, 2002
Using the set and get Member Functions
Tips: May 2002

Yehuda Shiran, Ph.D.
Doc JavaScript

You can expose a class's property simply by creating a member variable, and allowing other code to directly manipulate it, like in this example:

  class Airplane {
    var model: int;
  
    function Airplane() {
      model = 767;
    }
  } 
  var fifthJet : Airplane;
  fifthJet = new Airplane();
  fifthJet.model = 747;
This approach works fine, but it is not recommended to expose a class's variables to foreign code. It's better to create accessor functions. These are member functions that expose a class's properties as if they are member variables. These member functions are the set and get functions:

  class Airplane {
    var model: int;
  
    function Airplane() {
      model = 767;
    }
  
    function get JetModel() : int {
      return model;
    }
  
    function set JetModel(newModel : int) {
      model = newModel;
    }
  }
You set and get the jet's model with the JetModel() member function. Notice that the member function (JetModel) is different from the member property (model). You set the jet's model as follows:

  var sixthJet : Airplane;
  sixthJet = new Airplane();
  sixthJet.JetModel = 757;
You get the jet's model similarly:

  var seventhJet : Airplane;
  var myModel : int;
  seventhJet = new Airplane();
  myModel = seventhJet.JetModel;
To learn more about JScript .NET, go to Column 108, JScript .NET, Part II: Major Features.