使用服务将角度从一个下拉菜单传递到另一个下限

Question

我有两个下拉菜单和一张桌子。 我不知道如何将所选值从第一个下拉列表传递到第二个下拉列表。除非未将选定值传递给第二个下拉列表，否则第一个服务正常工作。

我的JavaScript：

 var myApp = angular.module("myApp", []);
    myApp.service('companiesService', ['$http', '$q', function ($http, $q) {
        var currentSettings = null;

        this.getList = function () {
            var def = $q.defer()
            if (currentSettings) {
                def.resolve(currentSettings);
            } else {
                $http.post('GetCompanies')
                  .then(function (response) {
                      var response = $.parseJSON(response.data)
                      currentSettings = response;
                      def.resolve(currentSettings);
                  });
            }
            return def.promise;
        }
    }]);

    myApp.service('docTypeService', ['$http', '$q', function ($http, $q) {
        var docSettings = null;
        this.getList = function () {
            var def = $q.defer()
            if (docSettings) {
                def.resolve(docSettings);
            } else {
                $http.post('GetDocTypes')
                  .then(function (response) {
                      var response = $.parseJSON(response.data)
                      docSettings = response;
                      def.resolve(docSettings);
                  });
            }
            return def.promise;
        }
    }]);

    myApp.service('allCurrentSettingsService', ['$http', '$q', function ($http, $q) {
        var allSettings = null;
        this.getList = function () {
            var def = $q.defer()
            if (allSettings) {
                def.resolve(allSettings);
            } else {
                $http.post('GetAllCurrentSettings')
                  .then(function (response) {
                      var response = $.parseJSON(response.data)
                      allSettings = response;
                      def.resolve(allSettings);
                  });
            }
            return def.promise;
        }
    }]);

    myApp.controller('myController', ['$scope', 'companiesService', 'docTypeService', 'allCurrentSettingsService',
      function ($scope, companiesService, docTypeService, allCurrentSettingsService) {
          $scope.currentSettings = '';
          companiesService.getList().then(function (value) {
              $scope.currentSettings = value;

          });

          $scope.docSettings = '';
          docTypeService.getList().then(function (value) {
              $scope.docSettings = value;

          });

          $scope.allSettings = '';
          allCurrentSettingsService.getList().then(function (value) {
              $scope.allSettings = value;

          });
      }
    ]);

我的HTML`

    <table>
        <tr>
            <td>Select a company:</td>
            <td>
                <div data-ng-controller="myController">
                    <select ng-model="dropdownvalue" ng-change="GetDocTypes(dropdownvalue)">
                        <option data-ng-repeat="currentSetting in currentSettings" value={{currentSetting.SCACCode}}>{{currentSetting.SCACCode}}</option>
                    </select>
                </div>
            </td>
        </tr>
        <tr>
            <td>Enter customer: </td>
            <td><div><input id="Text1" type="text" /></div></td>
        </tr>
        <tr>
            <td>Select document:</td>
            <td>
                <div ng-controller="myController">
                    <select>
                        <option>Select document</option>
                        <option ng-repeat="docSetting in docSettings" value="{{docSetting.Doc_Type}}">{{docSetting.Doc_Type}}</option>
                    </select>
                </div>
            </td>
        </tr>
    </table>

`

我的MVC控制器

`

public JsonResult GetDocTypes(string company)
        {
            var jsonString = string.Empty;

            string query = "SELECT * FROM Companies WHERE CompName = @Company";

            try
            {
                using (SqlConnection conn = new SqlConnection(connStringEbe))
                {
                    conn.Open();
                    using (SqlCommand command = new SqlCommand(query, conn))
                    {
                        DataTable dt = new DataTable();
                        command.Parameters.Add(new SqlParameter("@Company", company));

                        using (SqlDataReader rdr = command.ExecuteReader())
                        {
                            dt.Load(rdr);
                        }

                        command.Parameters.Clear();
                        jsonString = Newtonsoft.Json.JsonConvert.SerializeObject(dt, Formatting.None);
                        return Json(jsonString);
                    }
                }
            }
            catch (Exception ex)
            {
                Console.Write(ex.ToString());
                return Json(jsonString);
            }
        }

`