Question

We are using jQuery in our application for making AJAX calls. How do I inovke a method in a particular context using jQuery? In dojo we used to do it using dojo.hitch().
Is there something similar in jQuery? Below is the sample code that we are using. I need to execute the success handler in the context of SampleMethod. The below code should
give me exception since resultSetHandler is not available in the window context. Could you please let me know.

We are using jQuery version 1.3.2

function SampleMethod(){
    this.invokeProcedure=function(procedurePath){
        $.ajax({
                type: "GET",
                url: procedurePath,
                dataType: "json",
                success: resultSetHandler,
                error: errorHandler
            });
    }

    this.resultSetHandler=function(args){
        //Handle the result
    }

    this.errorHandler=function(args){
        //Handle the result
    }

}

var sampleObj=new SampleMethod();
sampleObj.invokeProcedure('url');

Answer 1

Just preserve this and wrap them in functions:

this.invokeProcedure=function(procedurePath){
        var savedThis = this;
        $.ajax({
                type: "GET",
                url: procedurePath,
                dataType: "json",
                success: function() { savedThis.resultSetHandler(); },
                error: function() { savedThis.errorHandler(); }
            });
    }

(Probably should pass the “success” function argument forward to “resultSetHandler” too.)

---

edit — the above will handle this sort of issue in the general case, but @Blaster correctly points out in a comment that the jQuery $.ajax mechanism provides a simpler solution. A context property can be set in the parameter object you pass in, and the value will be used as the context for the callbacks. That is, adding:

context: this,

to the $.ajax parameter object would make things work as you originally wrote it.