Angularjs中的动态多文件上载

Question

我正在开发angularjs应用程序，我可以动态地上传多个文件。让我解释一下这个场景。我将在API中获得所需的文档列表。我将绑定如下。

  <div class="upload-button" ng-repeat="file in files">
      <div class="upload-button-icon">
           <img src="images/folder-small.png">
           <div class="upload-text">{{file}}</div>
           <input type="file" id="file1" name="file1"  />
      </div>
  </div>

  <div class="button-container margin-top80">
       <input type="submit" value="{{ 'Save' | translate }}" ng-click="uploadFiles()" class="blue-button">
  </div>

我试过如下。

$scope.upload = function () {debugger;
        alert($scope.files.length + " files selected ... Write your Upload Code");
        var fileuploadurl = baseurl + 'api/Customer/UploadLeaseFiles/' + LoginID + '/' + "GOSI";
        for (var i = 0; i < $scope.files.length; i++) {
            var $file = $scope.files[i];
                 $upload.upload({
                 url: fileuploadurl,
                 file: $file,
                 progress: function (e) {
                 // wait...
             }
          })
         .then(function (data, status, headers, config) {
            alert('file is uploaded successfully');
         });
      }
     alert('file is uploaded successfully');
 };

此代码给出了错误eferenceError：$ upload未定义。

我想将这些文件提交给API。我可以知道我该怎么办？任何帮助将不胜感激。谢谢。