如何创建AngularJS jQueryUI自动完成指令

Question

我正在尝试创建一个使用jQueryUI的自动完成小部件的自定义指令。我希望这尽可能声明。这是所需的标记：

<div>
    <autocomplete ng-model="employeeId" url="/api/EmployeeFinder" label="{{firstName}} {{surname}}" value="id" />
</div>

因此，在上面的示例中，我希望指令对指定的url进行AJAX调用，并在返回数据时，在文本框中显示从结果中的表达式计算出的值，并将id属性设置为员工编号。这是我对指令的尝试。

app.directive('autocomplete', function ($http) {
    return {
        restrict: 'E',
        replace: true,
        template: '<input type="text" />',
        require: 'ngModel',

        link: function (scope, elem, attrs, ctrl) {
            elem.autocomplete({
                source: function (request, response) {
                    $http({
                    url: attrs.url,
                    method: 'GET',
                    params: { term: request.term }
                })
                .then(function (data) {
                    response($.map(data, function (item) {
                        var result = {};

                        result.label = item[attrs.label];
                        result.value = item[attrs.value];

                        return result;
                    }))
                });
                },

                select: function (event, ui) {                    
                    ctrl.$setViewValue(elem.val(ui.item.label));                    

                    return false;
                }
            });
        }
    }    
});

因此，我有两个问题-如何评估标签属性中的表达式以及如何将值属性中的属性设置为我的范围内的ngModel。

Answer 1

这是我更新的指令

(function () {
'use strict';

angular
    .module('app')
    .directive('myAutocomplete', myAutocomplete);

myAutocomplete.$inject = ['$http', '$interpolate', '$parse'];
function myAutocomplete($http, $interpolate, $parse) {

    // Usage:

    //  For a simple array of items
    //  <input type="text" class="form-control" my-autocomplete url="/some/url" ng-model="criteria.employeeNumber"  />

    //  For a simple array of items, with option to allow custom entries
    //  <input type="text" class="form-control" my-autocomplete url="/some/url" allow-custom-entry="true" ng-model="criteria.employeeNumber"  />

    //  For an array of objects, the label attribute accepts an expression.  NgModel is set to the selected object.
    //  <input type="text" class="form-control" my-autocomplete url="/some/url" label="{{lastName}}, {{firstName}} ({{username}})" ng-model="criteria.employeeNumber"  />

    //  Setting the value attribute will set the value of NgModel to be the property of the selected object.
    //  <input type="text" class="form-control" my-autocomplete url="/some/url" label="{{lastName}}, {{firstName}} ({{username}})" value="id" ng-model="criteria.employeeNumber"  />

    var directive = {            
        restrict: 'A',
        require: 'ngModel',
        compile: compile
    };

    return directive;

    function compile(elem, attrs) {
        var modelAccessor = $parse(attrs.ngModel),
            labelExpression = attrs.label;

        return function (scope, element, attrs) {
            var
                mappedItems = null,
                allowCustomEntry = attrs.allowCustomEntry || false;

            element.autocomplete({
                source: function (request, response) {
                    $http({
                        url: attrs.url,
                        method: 'GET',
                        params: { term: request.term }
                    })
                    .success(function (data) {
                        mappedItems = $.map(data, function (item) {
                            var result = {};

                            if (typeof item === 'string') {
                                result.label = item;
                                result.value = item;

                                return result;
                            }

                            result.label = $interpolate(labelExpression)(item);

                            if (attrs.value) {
                                result.value = item[attrs.value];
                            }
                            else {
                                result.value = item;
                            }

                            return result;
                        });

                        return response(mappedItems);
                    });
                },

                select: function (event, ui) {
                    scope.$apply(function (scope) {
                        modelAccessor.assign(scope, ui.item.value);
                    });

                    if (attrs.onSelect) {
                        scope.$apply(attrs.onSelect);
                    }

                    element.val(ui.item.label);

                    event.preventDefault();
                },

                change: function () {
                    var
                        currentValue = element.val(),
                        matchingItem = null;

                    if (allowCustomEntry) {
                        return;
                    }

                    if (mappedItems) {
                        for (var i = 0; i < mappedItems.length; i++) {
                            if (mappedItems[i].label === currentValue) {
                                matchingItem = mappedItems[i].label;
                                break;
                            }
                        }
                    }

                    if (!matchingItem) {
                        scope.$apply(function (scope) {
                            modelAccessor.assign(scope, null);
                        });
                    }
                }
            });
        };
    }
}
})();