AngularJS - 上传对话框中的未定义文件

Question

我在使用AngularJS + Material和上传对话框时遇到了一些问题。我认为原因与范围有关，因为当我选择要上传的文件并单击 md-button 时，console.log命令（在控制器块中）显示我＆＃34; 文件未定义 ＆＃34;并且后端没有到达数据。

这是我的代码。

模板

<md-dialog aria-label="Carica foto">
  <form ng-cloak>
    <md-toolbar>
      <div class="md-toolbar-tools">
        <h2>Upload photo</h2>
        <span flex></span>
        <md-button class="md-icon-button" ng-click="cancel()">
          <md-icon md-svg-src="img/icons/ic_close_24px.svg" aria-label="Close dialog"></md-icon>
        </md-button>
      </div>
    </md-toolbar>
    <md-dialog-content>
      <div class="md-dialog-content">
        <p>Choose photo</p>
        <br/><br/>
        <input type = "file" file-model="fotoBadge"/>
      </div>
    </md-dialog-content>
    <md-dialog-actions layout="row">
      <span flex></span>
      <md-button ng-click="uploadFile()">Upload</md-button>
    </md-dialog-actions>
  </form>
</md-dialog>

指令

app.directive('fileModel', ['$parse', function ($parse) {
    return {
        restrict: 'A',
        link: function(scope, element, attrs) {
         var model = $parse(attrs.fileModel);
         var modelSetter = model.assign;

         element.bind('change', function(){
            scope.$apply(function(){
               modelSetter(scope, element[0].files);
            });
         });
        }
   };
}]);

服务

app.service('fileUploadSrv', ['$http', function ($http) {
    this.uploadFileToUrl = function(file, uploadUrl){
    var fd = new FormData();
    fd.append('file', file);

    $http.post(uploadUrl, fd, {
        transformRequest: angular.identity,
        headers: {'Content-Type': undefined}    })
    .success(function(){
               })
    .error(function(){
               });      }
}]);

控制器

  function DialogController($scope, $mdDialog) {
    $scope.hide = function() {
      $mdDialog.hide();
    };
    $scope.cancel = function() {
      $mdDialog.cancel();
    };
    $scope.uploadFile = function(answer) {
       var file = $scope.fotoBadge;

       console.log('file is ' + file);

       var uploadUrl = "/be/fileUpload";
       fileUploadSrv.uploadFileToUrl(file, uploadUrl);

      $mdDialog.hide(answer);
    };
  }

提前致谢。

的Davide