我是角的新手。我试图从HTML“文件”字段读取上传的文件路径,每当“更改”发生在这个字段上。如果我使用“onChange”,它可以工作,但当我以angular的方式使用“ng-change”时,它就不起作用了。

<script>
   var DemoModule = angular.module("Demo",[]);
   DemoModule .controller("form-cntlr",function($scope){
   $scope.selectFile = function()
   {
        $("#file").click();
   }
   $scope.fileNameChaged = function()
   {
        alert("select file");
   }
});
</script>

<div ng-controller="form-cntlr">
    <form>
         <button ng-click="selectFile()">Upload Your File</button>
         <input type="file" style="display:none" 
                          id="file" name='file' ng-Change="fileNameChaged()"/>
    </form>  
</div>

fileNameChaged()从不调用。Firebug也不会显示任何错误。


当前回答

类似于这里的其他一些很好的答案,我写了一个指令来解决这个问题,但是这个实现更紧密地反映了附加事件的角度方式。

你可以像这样使用指令:

HTML

<input type="file" file-change="yourHandler($event, files)" />

如您所见,您可以将所选择的文件注入到事件处理程序中,就像您将$event对象注入到任何ng事件处理程序中一样。

Javascript

angular
  .module('yourModule')
  .directive('fileChange', ['$parse', function($parse) {

    return {
      require: 'ngModel',
      restrict: 'A',
      link: function ($scope, element, attrs, ngModel) {

        // Get the function provided in the file-change attribute.
        // Note the attribute has become an angular expression,
        // which is what we are parsing. The provided handler is 
        // wrapped up in an outer function (attrHandler) - we'll 
        // call the provided event handler inside the handler()
        // function below.
        var attrHandler = $parse(attrs['fileChange']);

        // This is a wrapper handler which will be attached to the
        // HTML change event.
        var handler = function (e) {

          $scope.$apply(function () {

            // Execute the provided handler in the directive's scope.
            // The files variable will be available for consumption
            // by the event handler.
            attrHandler($scope, { $event: e, files: e.target.files });
          });
        };

        // Attach the handler to the HTML change event 
        element[0].addEventListener('change', handler, false);
      }
    };
  }]);

其他回答

我做了一个小指令来监听文件输入的变化。

View JSFiddle

view.html:

<input type="file" custom-on-change="uploadFile">

controller.js:

app.controller('myCtrl', function($scope){
    $scope.uploadFile = function(event){
        var files = event.target.files;
    };
});     

directive.js:

app.directive('customOnChange', function() {
  return {
    restrict: 'A',
    link: function (scope, element, attrs) {
      var onChangeHandler = scope.$eval(attrs.customOnChange);
      element.on('change', onChangeHandler);
      element.on('$destroy', function() {
        element.off();
      });

    }
  };
});

简单的方法是编写自己的指令绑定到“change”事件。 只是让你们知道IE9不支持FormData所以你不能从change事件中得到file对象。

你可以使用ng-file-upload库,它已经支持IE的FileAPI polyfill,并简化了将文件发布到服务器的过程。它使用一个指令来实现这一点。

<script src="angular.min.js"></script>
<script src="ng-file-upload.js"></script>

<div ng-controller="MyCtrl">
  <input type="file" ngf-select="onFileSelect($files)" multiple>
</div>

JS:

//inject angular file upload directive.
angular.module('myApp', ['ngFileUpload']);

var MyCtrl = [ '$scope', 'Upload', function($scope, Upload) {
  $scope.onFileSelect = function($files) {
    //$files: an array of files selected, each file has name, size, and type.
    for (var i = 0; i < $files.length; i++) {
      var $file = $files[i];
      Upload.upload({
        url: 'my/upload/url',
        data: {file: $file}
      }).then(function(data, status, headers, config) {
        // file is uploaded successfully
        console.log(data);
      }); 
    }
  }
}];

这个指令也会传递选定的文件:

/**
 *File Input - custom call when the file has changed
 */
.directive('onFileChange', function() {
  return {
    restrict: 'A',
    link: function (scope, element, attrs) {
      var onChangeHandler = scope.$eval(attrs.onFileChange);

      element.bind('change', function() {
        scope.$apply(function() {
          var files = element[0].files;
          if (files) {
            onChangeHandler(files);
          }
        });
      });

    }
  };
});

HTML的使用方法:

<input type="file" ng-model="file" on-file-change="onFilesSelected">

在我的控制器中:

$scope.onFilesSelected = function(files) {
     console.log("files - " + files);
};

使用ng-change1的“files-input”指令的工作演示

要使<input type=file>元素使用ng-change指令,它需要一个使用ng-model指令的自定义指令。

<input type="file" files-input ng-model="fileList" 
       ng-change="onInputChange()" multiple />

演示

angular.module("app",[]) .directive("filesInput", function() { return { require: "ngModel", link: function postLink(scope,elem,attrs,ngModel) { elem.on("change", function(e) { var files = elem[0].files; ngModel.$setViewValue(files); }) } } }) .controller("ctrl", function($scope) { $scope.onInputChange = function() { console.log("input change"); }; }) <script src="//unpkg.com/angular/angular.js"></script> <body ng-app="app" ng-controller="ctrl"> <h1>AngularJS Input `type=file` Demo</h1> <input type="file" files-input ng-model="fileList" ng-change="onInputChange()" multiple /> <h2>Files</h2> <div ng-repeat="file in fileList"> {{file.name}} </div> </body>

我这样做过;

<!-- HTML -->
<button id="uploadFileButton" class="btn btn-info" ng-click="vm.upload()">    
<span  class="fa fa-paperclip"></span></button>
<input type="file" id="txtUploadFile" name="fileInput" style="display: none;" />
// self is the instance of $scope or this
self.upload = function () {
   var ctrl = angular.element("#txtUploadFile");
   ctrl.on('change', fileNameChanged);
   ctrl.click();
}

function fileNameChanged(e) {
    console.log(self.currentItem);
    alert("select file");
}