Jquery UI - 显示值而不是标签的框

Question

当我选择下拉列表时，它不显示标签，而是显示值。如何让它正常工作？这是我的代码：

            $("#mainIngredientAutoComplete").autocomplete({
                source: function (request, response) {
                    var matcher = new RegExp($.ui.autocomplete.escapeRegex(request.term), "i");
                    $.ajax({
                        url: "../api/IngredientChoices",
                        dataType: "json",
                        success: function (data) {
                            response($.map(data, function (v, i) {
                                var text = v.MainName;
                                if (text && (!request.term || matcher.test(text))) {
                                    return {
                                        label: v.MainName,
                                        value: v.MainItemID
                                    };
                                }
                            }));
                        }
                    });
                },
                minLength: 2,
                select: function (event, ui) {
                    $("#mainIngredientID").val(ui.item.value);
                    $("#mainIngredientAutoComplete").val(ui.item.label);
                }
            });