jQuery Deferred - 得到链式ajax调用的结果

Question

以下问题 - 我必须多次调用ajax函数,当所有函数都完成后,将所有结果都放入数组中.我想出了这个:

function doAjax(xx){
var xdata = {json: $.toJSON({name: xx}),
            delay: 1};
return $.ajax({
    url:"/echo/json/",
    data:xdata,
    type:"POST"
});

}

var carr = [doAjax('a'),doAjax('b'),doAjax('c'),doAjax('d')]
var result = [];

$.when( carr )
    .done(function(data){
        console.log(data);
        $.each(data, function(ix,val){
            console.log(val.name);
        });
    });

这里小提琴:http://jsfiddle.net/Fkd9n/

一切似乎工作正常,"console.log(data)"用响应文本写出对象,但"console.log(val.name)"始终是"未定义".那么一旦完成所有调用,如何将所有结果联合在一个数组中？

谢谢!

Answer 1

如果您知道有多少Ajax-Calls,只需使用$ .when()

$.when(doAjax('a'),doAjax('b'),doAjax('c'),doAjax('d'))
.then(function(result_a,result_b,result_c,result_d) {
    console.log("Result from query a: " + result_a);
    console.log("Result from query b: " + result_b);
    console.log("Result from query c: " + result_c);
    console.log("Result from query d: " + result_d);
});

如果您不知道有多少个ajax调用,您可以自己管理延迟对象.

// altered version of doAjax()
function doAjax(number,dObject) {
    var xdata = {json: $.toJSON({name: number}), delay: 1};
    $.ajax({
        url:"/echo/json/",
        data:xdata,
        type:"POST",
        success: function(data) {
            results.push(data);
            dObject.resolve();
        }
    });
}

// array that will contain all deferred objects
var deferreds = [];

// array that will contain all results
var results = [];

// make the ajax calls
for (var i = 0; i < someNumber; i++) {
    var dObject = new $.Deferred();
    deferreds.push(dObject);
    doAjax(i,dObject);
}

// check if all ajax calls have finished
$.when.apply($, deferreds).done(function() {
    console.log(results);
});

魔术附带函数apply(),它为一个函数的参数创建一个数组.