Question

I define a class like this:

var LoadingPolecy={
    initialize:function(){
        return function(){
               this.initialize.apply(this,arguments);
        }    
    }
}
var AjaxLoadingPolecy= LoadingPolecy.initialize();
AjaxLoadingPolecy.prototype={
    initialize:function(name){
        this.name=name;
    },
    AjaxStartPolecy : function(){
        ...
    },
    AjaxStopPolecy : function(){
        ...   
    },
    SetName : function(name){
        ...
    }
}
var TempLoadingPolecy=LoadingPolecy.initialize();
TempLoadingPolecy.prototype={
    initialize:function(displayArea,source,data){
        this.loadingMsgPolecy = new AjaxLoadingPolecy();
                ...
        },
        StartLoadingTempPolecy : function(callback){
        this.loadingMsgPolecy.SetName('view');
        this.loadingMsgPolecy.AjaxStartPolecy();
        var a = $.ajax({
          ...
          success:function(html){
              callback(html);
          }
        });
    },
        EndLoadingTempPolecy : function(html){
           //Cannot call method 'AjaxStopPolecy' of undefined error
        this.loadingMsgPolecy.AjaxStopPolecy();
                ....
        }
}

I seems the object in this has been changed, how can I call/ use the variables that I defined in initialize?

Answer 1

The ajax success callback (and the same for most other callbacks) does not give you the same this. But, you can save the previous copy of this into another variable and access it that way:

I don’t understand which part of your code you are asking about, but here’s a simple example that you can adapt from:

initialize:function(displayArea,source,data){
    StartLoadingTempPolecy : function(callback) {
        this.loadingMsgPolecy.SetName('view');
        this.loadingMsgPolecy.AjaxStartPolecy();
        // save copy of `this` for future use in the success handler
        var self = this;
        var a = $.ajax({
          ...
          success:function(html) {
              // you can use the variable `self` here to access the previous this ptr
              callback(html);
          }
    });
},