dart上传文件输入类型文件 [英] dart upload file input type file

问题描述

使用Dart和Golang创建一个小型应用程序，并希望将文件上传到服务器.

Using Dart and Golang for a small app and looking to upload a file to server.

找到了类似的内容并将其放在我的.dart文件中:

Found something like this and placed it in my .dart file:

InputElement uploadInput = query('#file'); // my input type file

  uploadInput.on.change.add((e) {
    // read file content as dataURL
    final files = uploadInput.files;
    if (files.length == 1) {
      final file = files[0];
      final reader = new FileReader();
      reader.on.load.add((e) {
       sendDatas(reader.result);
      });
      reader.readAsDataURL(file);
    }
  });

但出现以下错误:

Uncaught TypeError: Cannot read property 'get$on' of null 

知道如何处理吗?

我的目标:使用输入类型的文件将文件上传到服务器(文件大小为<1MB)

my goal: using input type file upload file to server (file size, < 1MB)

推荐答案

最后更改了代码，这是最终的工作功能，使用DART上传文件:

Finally changed the code and this is the final working function, uploading file with DART:

updatefileToPlay(Event e, dynamic data, FileUploadInputElement el) {

    final files = el.files;
        if (files.length == 1) {
          final file = files[0];
          final reader = new FileReader();

          reader.onLoad.listen((e) {

            FormData data = new FormData(); // from dart:html
                data.append("file", file);

                HttpRequest.request('/upload?id='+message.id, method: 'POST', sendData: data).then((HttpRequest r) {
                  if (r.readyState == HttpRequest.DONE &&
                      (r.status == 200 || r.status == 0)) {
                    window.alert("upload complete");
                  }
                });
          });
          reader.readAsDataUrl(file);
        }
  }

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