Passing path to uploaded file from HTML5 drag & drop to input field

Question

I\'m working on an application (in Node.js, which is irrelevant for this case) which allows the user to upload an image. It works fine using a form with an input (type=\"fil

Answer 1

I find that the hidden field set in reader.onload (see answer by @challet) is not set when acccessed in code behind. I am using asp.net and a WebForms project. To access the hidden fields I have to prepend MainContent_ to the field names. aspx code is below

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Drag image to this Drop Zone ...
    
 
    
    
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I access the hidden fields from c# as shown below

protected void btnDrop_Click(object sender, EventArgs e)
         {
             string FileName = DroppedFileName.Value;
             string FileContent = DroppedFileContent.Value;
         }

If I use Internet Explorer as the target browser (not running VS as Admin as this disables drag/drop!) and set a breakpoint in the reader.onload() function the hidden field DroppedFileContent contains the encoded file content, but when I try to access it from btnDrop_Click it only contains "Test" as set before reader.onload() and does not contain the encoded file content. The field DroppedFileNam.Value is as set in the Javascript.