拖放和提交文件以上传

Drag,Drop and Submit files to upload

我正在 拖放 文件,例如 asp.net mvc 5 中的 this, 但我的要求是当我拖动文件时,它不应该立即上传。 首先拖动文件, 然后单击 按钮 ("Enter MetaData") 为每个文件输入一些强制属性(元数据名称、类别等...), 然后点击其他按钮(提交)提交上传。

通常当我们拖动文件时,它会立即上传,我必须停止它并在单击按钮时执行(在填写其他字段后)。甚至任何具有类似功能的第三方 js 库?

我用谷歌搜索了很多,但没有得到预期的结果。 有人可以指导我如何满足此要求或提供一些链接来满足此要求。

您链接到的示例代码似乎使用了 jquery.filedrop.js,它是由 Weixi Yen 编写的。您需要从 project home 下载并使用最新版本才能正常工作。

您还应该下载并使用比与该示例代码捆绑在一起的更高版本的 jquery。我用 jquery 1.9.1.

测试过这个

要使用您选择的 jquery 扩展,您需要利用 beforeSend 选项,并提供您自己的函数。您还需要存储对每个文件提供给您的自定义函数的 done() 函数的引用,以便稍后调用它们,从而导致文件上传。

如果您希望为每个文件显示元框,则需要在每个文件的基础上附加适当的 html 以允许用户填写它们。

我建议的代码摘要如下:

var uploads_to_call = [];  // the global to store all the file upload callbacks

$('#dropzone').filedrop({
    fallback_id: 'upload_button',   // an identifier of a standard file input element, becomes the target of "click" events on the dropzone
    url: 'upload.php',              // upload handler, handles each file separately, can also be a function taking the file and returning a url
    // other important parameters related to upload, read the documentation for details

    // this is the important custom function you need to supply
    beforeSend: function(file, i, done) {
        // file is a file object
        // i is the file index
        // call done() to start the upload

        // this is just to clone meta boxes for the user to fill in for each file
        // it also fills in the filename so that it's obvious which meta boxes
        // are for which files
        $("#perfile").children().clone()
           .appendTo("#allmeta")
           .children(".filename").html(file.name);

        // this pushes the done() callback into the global mentioned earlier
        // so that we can call it later
        uploads_to_call.push(done);
    },
    afterAll: function() {
        // runs after all files have been uploaded or otherwise dealt with
        // you should possibly put code in here to clean up afterwards
    }
});

// set a handler to upload the files when the submit button is clicked
$("#submit").click(function(){
    $.each(uploads_to_call, function(i, upcall) {
        upcall();
    });
});

与html类似如下:

<form>
    <div id="dropzone"></div>
    <div id="allmeta"></div>
    <button id="submit">submit</button>
</form>

<div id="perfile">
    <div class="meta">
        <span class="filename"></span>
        <input type="text" placeholder="meta"/>
        <input type="text" placeholder="meta"/>
    </div>
</div>

div#perfile 应该有 css 来隐藏它,因为它只用于包含每次拖入文件时要克隆到表单中的 div。

我已经创建了一个概念验证 jsfiddle here,显然这实际上不允许上传文件,但它显示了 JS 方面的工作。您需要向下滚动到 javascript 面板的底部以查看自定义代码 - 顶部的内容仅包括您应该从项目主页下载的 javascript 扩展。

这应该足以让 asp.net 方面的工作正常进行。您只需要 post 用户以您认为合适的方式提供的额外元数据。

显然这是准系统,您应该根据需要充实它。

根据我的研究,在 jquery.filedrop 中无法手动处理上传。您可以使用 event functions like bellow to prompt 用户之一输入一些额外的参数,如元数据等......然后将它们附加到发送数据中,如下所示:

$('#myElement').fileDrop({
    data: {
        param1: 'value1',           // send POST variables
        param2: function(){
            return calculated_data; // calculate data at time of upload
        },
    },
    onFileRead : function(fileCollection){
        $.each(fileCollection, function(){
            //Do stuff with fileCollection here!
        });
    },
    drop: function() {
        // user drops file
    },
    beforeSend: function(file, i, done) {
        // file is a file object
        // i is the file index
        // call done() to start the upload
    },
    // Called before each upload is started
    beforeEach: function(file){
        //do some stuff here
    }
});

你试过了吗Dropzone.jshttp://www.dropzonejs.com/ 他们似乎支持您正在寻找的功能。 以下是相关页面的摘录。我自己没有尝试过,但纯粹基于值得一试的文档来检查它是否符合您的要求。

If you have autoProcessQueue disabled, you’ll need to call .processQueue() yourself.

This can be useful if you want to display the files and let the user click an accept button to actually upload the file(s).

由于您正在寻找库,我为您开发了一个完整的香草 Javascript 解决方案,如下所示:

/* as soon as all the elements of the page has been loaded */
document.addEventListener('DOMContentLoaded', function() {
  /* we reference the most used elements into variables, making it easier to use later */
  var dropzone = document.getElementById('dropzone'),
      dialog = document.getElementById('dropzone-dialog'),
      submit = document.getElementById('submit'),
      progress = document.querySelector('progress'),
      _current = null; // we keep track what file the user is changing its metadata

  /* when the user drags something over our div, we must prevent the browser's default
     behavior and we change a CSS class only for usability reasons */
  dropzone.addEventListener('dragover', function(e) {
    e.preventDefault();
    dropzone.classList.add('dragging');
  });

  /* when the user leaves our div, we must remove the CSS class we put before */
  dropzone.addEventListener('dragleave', function(e) {
    e.preventDefault();
    dropzone.classList.remove('dragging');
  });

  /* that's the heart of our code,
     when the user effectively drops one or more files into the div */
  dropzone.addEventListener('drop', function(e) {
    /* again we must prevent the default browser's behavior,
       and we need to remove the CSS clas we put before */
    e.preventDefault();
    dropzone.classList.remove('dragging');
    submit.classList.add('hidden');

    /* we change our div's text */
    dropzone.textContent = 'File(s) dropped:';

    /* we create an UL element, so we can loop through the files make a list */
    var ul = document.createElement('ul');
    /* since the files property is not an array, but it is Array-like,
       we call the Array.prototype.forEach method passing the files to be the context */
    [].forEach.call(e.dataTransfer.files, function(file) {
      /* for each file the user has dropped, we create a LI and an anchor inside it */
      var li = document.createElement('li');
      var a = document.createElement('a');

      a.href = '#';
      a.textContent = file.name;
      a.title = 'Enter metadata';
      
      /* we create a property __file into our anchor to reference the dropped file */
      a.__file = file;

      li.appendChild(a);
      ul.appendChild(li);
    });
    dropzone.appendChild(ul);
  });

  /* here, we add a 'click' event handler to our div dropzone,
     so we can add the file's metadata behavior.
     the idea here is to make an event delegation, that is, when the user clicks anywhere
     inside the div, we see if the element that was clicked is one of the files */
  dropzone.addEventListener('click', function(e) {
    var el = e.target;

    /* if the element clicked is an anchor, it's because it's one of the files */
    if (el.tagName === 'A') {
      /* we prevent the browser's default behavior */
      e.preventDefault();
      /* we keep track that the current clicked file/anchor is the last clicked */
      _current = el;
      
      /* and then, we show our dialog, so the user can input the file's metadata */
      dialog.classList.remove('hidden');
      /* we set focus on the first element of the dialog, only for usability reasons */
      dialog.querySelector('#name').focus(); 
      
    }
  });

  /* we add an event handler to the dialog's close button,
     so it can effectively close the dialog */
  dialog.querySelector('.close').addEventListener('click', clearDialog);
  
  /* this is the second heart of our code.
     we add an event handler to the dialog's save button,
     so it can handle the saving of metadata */
  dialog.querySelector('#save').addEventListener('click', function() {
    /* here you can add any validation you want, e.g: required fields, etc */
    
    /* if everything was cool, we set a new property __dataFile to our anchor
       so, we can save the metadata for future use (the form submission) */
    _current.__dataFile = {
      name: dialog.querySelector('#name').value,
      category: dialog.querySelector('#category').value
      /* put here any other metadata property you will save */
    };
    
    /* when the user saves the metadata, we add a CSS class only for usability reasons */
    _current.classList.add('finished');

    /* then, we keep track if there is any file with no metadata saved yet */
    var btnsLeft = [].filter.call(dropzone.querySelectorAll('a'), function(el, i) {
      return !('__dataFile' in el);
    });

    /* if all the files' metadatas have been saved, we show the submit button */
    if (btnsLeft.length === 0)
      submit.classList.remove('hidden');

    /* and we clear/close our dialog */
    clearDialog();
  });

  function clearDialog() {
    /* when the dialog is closed, we set our current-clicked anchor to null */
    _current = null;

    /* we clean all the input fields of the dialog */
    [].forEach.call(dialog.querySelectorAll('input'), function(el, i) {
      el.value = '';
    });

    /* and we effectively hide/close the dialog */
    dialog.classList.add('hidden');
  }

  /* this is third heart of our code.
     we add a click event handler to our submit button,
     so we can effectively send our form to the server */
  submit.querySelector('button').addEventListener('click', function(e) {
    e.preventDefault(); // we must prevent the browser's default behavior

    /* we create a XMLHttpRequest to send our AJAX to the server */
    var xhr = new XMLHttpRequest();

    /* we add a 'load' event handler, so we can keep track when the upload is finished */
    xhr.addEventListener('load', finished);
    /* we do the same for progress and error, so we can inform our user what's going on */
    xhr.upload.addEventListener('progress', progress);
    xhr.addEventListener('error', error);
    
    /* now it's time to save all our data, so we create a FormData */
    var fd = new FormData();

    /* and for each anchor(file) inside our dropzone, we add new data to our FormData */
    [].forEach.call(dropzone.querySelectorAll('a'), function(el, i) {
      /* here we loop through our __dataFile previously created property,
         so we can add the file's metadata parameter */
      for (var prop in el.__dataFile) {
        /* since we are sending multiple files/metadatas,
           it's important to name our field with [] */
        fd.append(prop + '[]', el.__dataFile[prop]);
      }
      
      /* and then, we append the file itself - again, with the [] at the end */
      fd.append('file[]', e.__file);
    });

    /* now we open the xhr, and we effectively send the request to the server */
    xhr.open('POST', '/api/uploadfiles/'); // change for your API URL
    xhr.send(fd);
  });
  
  /* this is the xhr's progress, so we can update our HTMLProgressElement's percent */
  function progress(e) {
    progress.value = progress.innerHTML = (e.loaded / e.total * 100 | 0);
  }

  /* this is the xhr's finished event handler,
     we show a friendly message and hide the submit button */
  function finished(e) {
    progress.value = progress.innerHTML = 100;
    dropzone.innerHTML = '<h3>Files successfully uploaded</h3>';
    submit.classList.add('hidden');
  }
  
  /* this is the xhr's error event handler. If there is any known error, we show it */
  function error(e) {
    var xhr = e.target;
    submit.classList.add('hidden');
    dropzone.innerHTML = '<h3>Error while uploading</h3>' +
      (xhr.status ? '<span>' + xhr.status + ' - ' + xhr.statusText + '</span>' : '');
  }
});
#dropzone {
  width: 450px;
  height: 165px;
  background-color: #CCC;
  font: 16px Verdana;
  padding: 10px;
  box-sizing: border-box;
}
#dropzone.dragging {
  background-color: #EEE;
}
#dropzone > h3 {
  text-align: center;
}
#dropzone a {
  text-decoration: none;
}
#dropzone a:hover {
  text-decoration: underline;
}
#dropzone a.finished:after {
  content: ' √';
  color: green;
  font-weight: bold;
  text-decoration: none;
}
#dropzone ul {
  list-style: none;
  margin-left: 15px;
  padding: 0;
}
#dropzone li {
  margin-top: 8px;
}
#dropzone li:before {
  content: '> ';
}
.hidden {
  display: none;
}
.dialog {
  background-color: #AAAAFF;
  font-family: Verdana;
  padding: 12px;
  border-radius: 10px;
  width: 300px;
  height: 150px;
  position: absolute;
  top: 20px;
}
.dialog h3 {
  text-align: center;
}
.dialog .close {
  text-decoration: none;
  float: right;
}
.dialog .close:after {
  content: '✖';
  cursor: pointer;
}
.dialog > div {
  display: table;
}
.dialog > div > div {
  display: table-row;
}
.dialog > div > div > div,
.dialog > div > div > label {
  display: table-cell;
  padding: 2px 0 2px 10px;
}

#submit {
  height: 160px;
  width: 450px;
  text-align: right;
  position: fixed;
  top: 10px;
}
#submit button {
  font-size: 20px;
  padding: 10px;
  background-color: orange;
}

progress {
 width: 450px; 
}
<div id="dropzone">
  <h3>Drop your files here</h3>
</div>
<div>
  <progress min="0" max="100" value="0"></progress>
</div>
<div id="submit" class="hidden">
  <button>Submit</button>
</div>
<div id="dropzone-dialog" class="dialog hidden">
  <a class="close"></a>
  <h3>File Metadata</h3>
  <div>
    <div>
      <label for="name">
        Name
      </label>
      <div>
        <input id="name">
      </div>
    </div>
    <div>
      <label for="category">
        Category
      </label>
      <div>
        <input id="category">
      </div>
    </div>
    <div>
      <div></div>
      <div style="text-align: right">
        <button id="save">Save</button>
      </div>
    </div>
  </div>
</div>

上面的代码有完整的注释,但如果您需要任何帮助,请发表评论。