使用Angular JS进行文件选择

问题描述 投票:26回答:8

我想用AngularJS获取一个文件:

HTML:

<div ng-controller="TopMenuCtrl">
    <button class="btn" ng-click="isCollapsed = !isCollapsed">Toggle collapse</button>
    <input type="file" ng-model="filepick" ng-change="pickimg()" multiple />
    <output id="list"></output> 
</div>

JavaScript的:

angular.module('plunker', ['ui.bootstrap']);
function TopMenuCtrl($scope) {
    $scope.pickimg = function() {
        alert('a');
    };
}

如何在AngularJS onchange函数上绑定输入文件pickimg动作?我怎样才能操纵上传后的文件?

angularjs
8个回答
49
投票

Angular尚不支持输入[type = file]的ng-change,因此您必须自己滚动onchange实现。

首先,在HTML中,为onchange定义Javascript,如下所示:

<input ng-model="photo"
       onchange="angular.element(this).scope().file_changed(this)"
       type="file" accept="image/*" />

然后在Angular控制器代码中,定义函数:

$scope.file_changed = function(element) {

     $scope.$apply(function(scope) {
         var photofile = element.files[0];
         var reader = new FileReader();
         reader.onload = function(e) {
            // handle onload
         };
         reader.readAsDataURL(photofile);
     });
};

17
投票

我使用上面的方法尝试在选择新文件时加载预览图像,但是当我尝试这样做时它没有工作:

$scope.file_changed = function(element, $scope) {

     $scope.$apply(function(scope) {
         var photofile = element.files[0];
         var reader = new FileReader();
         reader.onload = function(e) {
            $scope.prev_img = e.target.result;
         };
         reader.readAsDataURL(photofile);
     });
});

我挖了更多,发现$ scope。$ apply应该在reader.onLoad中,否则更改$ scope变量不会工作,所以我做了以下工作:

$scope.file_changed = function(element) {

        var photofile = element.files[0];
        var reader = new FileReader();
        reader.onload = function(e) {
            $scope.$apply(function() {
                $scope.prev_img = e.target.result;
            });
        };
        reader.readAsDataURL(photofile);
 };

6
投票

Teemu解决方案不适用于IE9。

我已经将Flash polyfill的简单角度指令放在一起,用于不支持HTML5 FormData的浏览器,你也可以收听上传进度事件。

Kua zxsw poi但是:Kua zxsw poi

https://github.com/danialfarid/ng-file-upload

控制器:

http://angular-file-upload.appspot.com/

4
投票

以下是我的指令方法。

指示

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

<div ng-controller="MyCtrl">
  <input type="text" ng-model="additionalData">
  <div ngf-select ng-model="files" >
</div>

HTML

Upload.upload({
    url: 'my/upload/url',
    data: additionalData,
    file: files
  }).then(success, error, progress); 

调节器

angular
  .module('yourModule')
  .directive('fileChange', function() {
    return {
     restrict: 'A',
     scope: {
       handler: '&'
     },
     link: function (scope, element) {
      element.on('change', function (event) {
        scope.$apply(function(){
          scope.handler({files: event.target.files});
        });
      });
     }
    };
});

3
投票

使用上面的<input type="file" file-change handler="fileSelect(files)"> ,这是读取本地JSON文件的完整流程:

创建指令:

fileSelect = function (files) {
      var file = files[0];
      //you will get the file object here
}

HTML:

Madura's answer

使用Javascript:

angular
  .module('app.services')
  .directive('fileChange', function() {
    return {
     restrict: 'A',
     scope: {
       handler: '&'
     },
     link: function (scope, element) {
      element.on('change', function (event) {
        scope.$apply(function(){
          scope.handler({files: event.target.files});
        });
      });
     }
    };
});

2
投票

这是我为解决这个问题而写的一个轻量级指令,它反映了附加事件的角度方式。

您可以像这样使用指令:

HTML

<input type="file" file-change handler="fileSelect(files)">

如您所见,您可以将选定的文件注入事件处理程序,就像将$ event对象注入任何ng事件处理程序一样。

使用Javascript

$scope.fileSelect = function(files) {
  var file = files[0];
  var reader = new FileReader();
  reader.onload = function(e) {
    console.log("on load", e.target.result);
  }
  reader.readAsText(file);
}

0
投票

我做了一个指示。这是<input type="file" file-change="yourHandler($event, files)" /> 。 该应用程序适用于选择csvs并将其显示为html表。 使用on-file-change指令,您将能够在控制器本身中定义文件读取和解析(使用服务,可能是)逻辑,这将提供更大的灵活性。只是为了注释,传递给on-file-change属性的angular .module('yourModule') .directive('fileChange', ['$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); } }; }]); 函数将成为指令内输入更改事件的处理程序。

fiddle
ac.onFileChange
(function (angular, document) {

   angular
      .module("app.directives", [])
      .directive("onFileChange", ["$parse", function ($parse) {
         return {
            restrict: "A",
            link: function (scope, ele, attrs) {
               // onFileChange is a reference to the same function which you would define 
               // in the controller. So that you can keep your logic in the controller.
               var onFileChange = $parse(attrs.onFileChange.split(/\(/)[0])(scope)
               ele.on("change", onFileChange)
               ele.removeAttr("on-file-change")
            }
         }
      }])

   angular
      .module("app.services", [])
      .service("Parse", ["$q", function ($q) {
         var Parse = this
         Parse.csvAsGrid = function (file) {
            return $q(function (resolve, reject) {
               try {
                  Papa.parse(file, {
                     complete: function (results) {
                        resolve(results.data)
                     }
                  })
               } catch (e) {
                  reject(e)
               }
            })
         }
      }])

   angular
      .module("app", ["app.directives", "app.services"])
      .controller("appCtrl", ["$scope", "Parse", function ($scope, Parse) {
         var ac = this
         ac.fileName = ""
         ac.onFileChange = function (event) {
            if (!event.target.files.length) {
               return
            }
            Parse.csvAsGrid(event.target.files[0]).then(outputAsTable)
         }

         ac.clearInput = function (event) {
            var input = angular.element(event.target)
            input.val("")
            document.getElementById("output").innerHTML = ""
         }

         function outputAsTable(grid) {
            var table = ['<table border="1">']
            grid.map(function (row) {
               table.push('<tr>')
               row.map(function (cell) {
                  table.push('<td>' + cell.replace(/["']/g, "") + '</td>')
               })
               table.push('</tr>')
            })
            table.push('</table>')
            document.getElementById("output").innerHTML = table.join("\n")
         }
      }])

})(angular, document)

0
投票

使用ng-model-controller的指令:

table {
  border-collapse: collapse;
}

用法:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.0.0/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.8/angular.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/PapaParse/4.1.2/papaparse.min.js"></script>

<div ng-app="app" ng-controller="appCtrl as ac">
  <label>Select a comma delimited CSV file:-</label>  
  <input id="filePicker" type="file" on-file-change="ac.onFileChange(event)" ng-click="ac.clearInput($event)"/>{{ac.fileName}}  
</div>
<div id="output"></div>

有关更多信息,请参阅app.directive("selectNgFiles", function() { return { require: "ngModel", link: function postLink(scope,elem,attrs,ngModel) { elem.on("change", function(e) { var files = elem[0].files; ngModel.$setViewValue(files); }) } } });

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