如何从FilePicker获取[object file]，例如来自< input type = file>对于XHR POST请求？ [英] How to get an [object File] from FilePicker like from <input type=file> for XHR POST Request?

问题描述

再次问好，现在我需要一个来自FilePicker的[object File]来通过XHR Post Request发送它。

一个带< input type = file>的解决方案有效，但WinRT的FilePicker会更好 由于我需要一个仅限图像的缩略图视图。

< span style ="white-space：nowrap">解决方案是 

Hello again, now I need an [object File] from FilePicker to send it via XHR Post Request.
A solution with <input type=file> works, but it'll be better with WinRT's FilePicker due to I need an image-only thumbnail view.
The solution is 

input.addEventListener("change", function () {
            var file = this.files[0];<span style="font-family:arial,sans-serif; font-size:x-small"><span style="white-space:nowrap"><br/>formdata.append("photo", file);
                      log('file: ' + file)
                      var fd = new FormData();
                      fd.append('photo', file);
                      var xhr = new XMLHttpRequest();
                      MethodWithNoParametrs('photos.getWallUploadServer').then(function (result) {
                          xhr.open('POST', JSON.parse(result.responseText).response.upload_url + '&access_token=' + vk.Token);
                          xhr.send(fd);
                          xhr.onload = function () {
                              var json = JSON.parse(xhr.responseText);
                              log(xhr.responseText);
                              log(xhr.statusText);
                              Method('photos.saveWallPhoto?server=' + json.server + '&photo=' + json.photo + '&hash=' + json.hash).then(function (result) {
                                  log(result.responseText);
                                  Method('wall.post?attachment='+JSON.parse(result.responseText).response[0].id).then(function (result) {
                                      log(result.responseText);
                                  }, function (err) {
                                      log(err);
                                  });
                              })
                              
                          }
                      });</span></span>

推荐答案

嗨Moushen，

Hi Moushen,

我不知道是什么你要的是。 选择器会返回文件对象。

I am not sure what you are asking for.  The Pickers do return file object.

如果您询问如何使用XHR上传服务器的特定格式，则需要了解该格式是什么。 实现这一目标的最佳方法是使用成功案例并将其与XHR案例进行比较。 您可以使用工具
（如fiddler（ http://fiddler2.com ）来检查HTTP流量并查看您的差异是什么。 

If you are asking how to use XHR to upload a particular format for your server, you will need to understand what that format is.  The best way to accomplish this is to use a successful case and compare that to the XHR case.  You can use a tool like fiddler (http://fiddler2.com) to inspect the HTTP traffic and see what your differences are. 

-Jeff

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