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Web API Multi-file Upload Using Dropzone.js Specifying Dynamic Query String
<div class="jumbotron">
<form action="~/api/Upload" class="dropzone" enctype="multipart/form-data" id="dropzoneForm" method="post" name="dropzoneForm">
<div class="fallback">
<input multiple name="file" type="file"> <input type="submit" value="Upload">
<style type="text/css">
.dz-max-files-reached {
background-color: red;
<script type = "text/javascript" >
Dropzone.options.dropzoneForm = {
maxFiles: 20,
maxFilesize: 500,
init: function() {
this.on("processing", function(file) {
// Customize the upload URL by adding querystring
var baseUrl = $("#dropzoneForm").attr("action");
this.options.url = baseUrl + "?someParameter=someValue";
this.on("maxfilesexceeded", function(data) {
var res = eval('(' + data.xhr.responseText + ')');
this.on("addedfile", function(file) {
// Create the remove button
var removeButton = Dropzone.createElement("<button>Remove file<\/button>");
// Capture the Dropzone instance as closure.
var _this = this;
// Listen to the click event
removeButton.addEventListener("click", function(e) {
// Make sure the button click doesn't submit the form:
// Remove the file preview.
// If you want to the delete the file on the server as well,
// you can do the AJAX request here.
// Add the button to the file preview element.
public class UploadController : ApiControllerBase
public async Task<IHttpActionResult> Post()
if (!Request.Content.IsMimeMultipartContent())
throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
var provider = new MultipartMemoryStreamProvider();
await Request.Content.ReadAsMultipartAsync(provider);
var baseUploadPath = @"D:\Uploads\" + Request.QueryString["someParameter"];
foreach (var file in provider.Contents)
if (file.Headers.ContentLength > 0)
var fileName = file.Headers.ContentDisposition.FileName.Trim('\"');
var filePath = Path.Combine(baseUploadPath, fileName);
var buffer = await file.ReadAsByteArrayAsync();
File.WriteAllBytes(filePath, buffer);
return Ok();
catch (Exception ex)
var response = Request.CreateErrorResponse(HttpStatusCode.InternalServerError, ex);
throw new HttpResponseException(response);

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Owner Author

softwarerockstar commented Apr 25, 2017

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