如何确保循环中的第一项被响应值填充？

Question

我试图在循环内调用多个ajax请求以加载多个下拉列表。我尝试了顺序方式，但只在循环中的最后一项填充了值。

 var targetcontrols = [];
        var targetcontrols_array = targetControl.split(',');
        var targetsourcecontrols = [];
        var targetsource_array = targetSource.split(',');
        for(i=0; i < targetcontrols_array.length; i++)
        {
            var control_name=targetcontrols_array[i];
            var source=targetsource_array[i];
            $.ajax({
                url: action_url,
                type: 'POST',
                traditional: true,
                async: false,
                data: JSON.stringify( { allselected: allselected_flag, selectedIds: selectedvalues,targetControl:control_name,  targetSource: source, dependency: dependencyOptions } ),
                contentType: "application/json; charset=utf-8",
                dataType: 'json',
                success: function (response) {
                    //To clear existing items
                    var target= $("#"+response.targetControl);
                    target.multiselect('dataprovider', []);
                    var dropdown2OptionList = [];
                    for (i = 0; i < response.values.length; i++) {
                        dropdown2OptionList.push({
                            'label': response.values[i].text,
                            'value': response.values[i].value
                        })
                    }
                    console.log("--control"+control_name);
                    //re initialize the search plugin
                    target.multiselect('dataprovider', dropdown2OptionList);
                    target.multiselect('rebuild');
                }
            });

如何确保循环中的第一项也被响应值填充？

Answer 1

First of all if you use jquery, utilize it's full potential, instead of for loops, use $.each:

var targetcontrols = [];
        var targetcontrols_array = targetControl.split(',');
        var targetsourcecontrols = [];
        var targetsource_array = targetSource.split(',');
        $.each(targetcontrols_array, function(i, item)
        {
            var control_name=targetcontrols_array[i];
            var source=targetsource_array[i];
            $.ajax({
                url: action_url,
                type: 'POST',
                traditional: true,
                async: false,
                data: JSON.stringify( { allselected: allselected_flag, selectedIds: selectedvalues,targetControl:control_name,  targetSource: source, dependency: dependencyOptions } ),
                contentType: "application/json; charset=utf-8",
                dataType: 'json',
                success: function (response) {
                    //To clear existing items
                    var target= $("#"+response.targetControl);
                    target.multiselect('dataprovider', []);
                    var dropdown2OptionList = [];
                    $.each(response.values, function(v, vItems) {
                        dropdown2OptionList.push({
                            'label': response.values[v].text,
                            'value': response.values[v].value
                        })
                    });
                    console.log("--control"+control_name);
                    //re initialize the search plugin
                    target.multiselect('dataprovider', dropdown2OptionList);
                    target.multiselect('rebuild');
                }
            });
        });