1. It's very simple and easy to upload a file without Ajax
It's easy to upload a file in a synchronous form, where you just post the file and read a HttpPostedFile variable in the server side: In plain html form, take note of the form ectype property:
In view write this code:
@using (Html.BeginForm("Upload", "Fileupload", FormMethod.Post, new { enctype = "multipart/form-data" }))
{
<input type="file" name="file">
<input type="submit" value="OK">
}
And after this write this code in the controller
public class FileuploadController : Controller
{
//it should show index.cshtml view
public ActionResult Index()
{
return View();
}
[HttpPost]
public ActionResult Upload(HttpPostedFile file)
{
if (file != null && file.ContentLength > 0)
{ //now you have a non-empty file
//to save in a local directory
var fileName = Path.GetFileName(file.FileName);
var path = Path.Combine(Server.MapPath("~/Uploads"), fileName);
file.SaveAs(path);
}
return new EmptyResult();
}
}
2. But when you use the ajax form, it sends a null value in http posted file
To resolve this issue I use one js file that converts this in the I frame and easily uploads the file
That should work, no problem, but what if you have an ajax form, asynchronously, you will not be able to upload a file together with the other form fields. So, I've used a 3rd party javascript library to create a hidden iframe that will contain a file field.
Js file code is below:
jQuery.extend({
createUploadIframe: function (id, uri) {
//create frame
var frameId = 'jUploadFrame' + id;
if (window.ActiveXObject) {
var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />');
if (typeof uri == 'boolean') {
io.src = 'javascript:false';
}
else if (typeof uri == 'string') {
io.src = uri;
}
}
else {
var io = document.createElement('iframe');
io.id = frameId;
io.name = frameId;
}
io.style.position = 'absolute';
io.style.top = '-1000px';
io.style.left = '-1000px';
document.body.appendChild(io);
return io
},
createUploadForm: function (id, fileElementId) {
alert("ajaxfile" + id)
alert("ajaxfile" + fileElementId)
//create form
var formId = 'jUploadForm' + id;
var fileId = 'jUploadFile' + id;
var form = $('<form action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');
var oldElement = $('#' + fileElementId);
var newElement = $(oldElement).clone();
$(oldElement).attr('id', fileId);
$(oldElement).before(newElement);
$(oldElement).appendTo(form);
//set attributes
$(form).css('position', 'absolute');
$(form).css('top', '-1200px');
$(form).css('left', '-1200px');
$(form).appendTo('body');
return form;
},
ajaxFileUpload: function (s) {
alert("file");
// TODO introduce global settings, allowing the client to modify them for all requests, not only timeout
s = jQuery.extend({}, jQuery.ajaxSettings, s);
var id = new Date().getTime()
var form = jQuery.createUploadForm(id, s.fileElementId);
var io = jQuery.createUploadIframe(id, s.secureuri);
var frameId = 'jUploadFrame' + id;
var formId = 'jUploadForm' + id;
// Watch for a new set of requests
if (s.global && !jQuery.active++) {
jQuery.event.trigger("ajaxStart");
}
var requestDone = false;
// Create the request object
var xml = {}
if (s.global)
jQuery.event.trigger("ajaxSend", [xml, s]);
// Wait for a response to come back
var uploadCallback = function (isTimeout) {
var io = document.getElementById(frameId);
try {
if (io.contentWindow) {
xml.responseText = io.contentWindow.document.body ? io.contentWindow.document.body.innerHTML : null;
xml.responseXML = io.contentWindow.document.XMLDocument ? io.contentWindow.document.XMLDocument : io.contentWindow.document;
} else if (io.contentDocument) {
xml.responseText = io.contentDocument.document.body ? io.contentDocument.document.body.innerHTML : null;
xml.responseXML = io.contentDocument.document.XMLDocument ? io.contentDocument.document.XMLDocument : io.contentDocument.document;
}
} catch (e) {
jQuery.handleError(s, xml, null, e);
}
if (xml || isTimeout == "timeout") {
requestDone = true;
var status;
try {
status = isTimeout != "timeout" ? "success" : "error";
// Make sure that the request was successful or notmodified
if (status != "error") {
// process the data (runs the xml through httpData regardless of callback)
var data = jQuery.uploadHttpData(xml, s.dataType);
// If a local callback was specified, fire it and pass it the data
if (s.success)
s.success(data, status);
// Fire the global callback
if (s.global)
jQuery.event.trigger("ajaxSuccess", [xml, s]);
} else
jQuery.handleError(s, xml, status);
} catch (e) {
status = "error";
jQuery.handleError(s, xml, status, e);
}
// The request was completed
if (s.global)
jQuery.event.trigger("ajaxComplete", [xml, s]);
// Handle the global AJAX counter
if (s.global && ! --jQuery.active)
jQuery.event.trigger("ajaxStop");
// Process result
if (s.complete)
s.complete(xml, status);
jQuery(io).unbind()
setTimeout(function () {
try {
$(io).remove();
$(form).remove();
} catch (e) {
jQuery.handleError(s, xml, null, e);
}
}, 100)
xml = null
}
}
// Timeout checker
if (s.timeout > 0) {
setTimeout(function () {
// Check to see if the request is still happening
if (!requestDone) uploadCallback("timeout");
}, s.timeout);
}
try {
// var io = $('#' + frameId);
var form = $('#' + formId);
$(form).attr('action', s.url);
$(form).attr('method', 'POST');
$(form).attr('target', frameId);
if (form.encoding) {
form.encoding = 'multipart/form-data';
}
else {
form.enctype = 'multipart/form-data';
}
$(form).submit();
} catch (e) {
jQuery.handleError(s, xml, null, e);
}
if (window.attachEvent) {
document.getElementById(frameId).attachEvent('onload', uploadCallback);
}
else {
document.getElementById(frameId).addEventListener('load', uploadCallback, false);
}
return { abort: function () { } };
},
uploadHttpData: function (r, type) {
var data = !type;
data = type == "xml" || data ? r.responseXML : r.responseText;
// If the type is "script", eval it in global context
if (type == "script")
jQuery.globalEval(data);
// Get the JavaScript object, if JSON is used.
if (type == "json")
eval("data = " + data);
// evaluate scripts within html
if (type == "html")
jQuery("<div>").html(data).evalScripts();
//alert($('param', data).each(function(){alert($(this).attr('value'));}));
return data;
}
})
//index.cshtml view
<script src="@Url.Content("~/Scripts/ajaxfileupload.js")"
type="text/javascript"></script>
<script type="text/javascript">
function ajaxFileUpload() {
$.ajaxFileUpload
(
{
url: "@Url.Action("UploadAttachment", "File")",
secureuri: false,
fileElementId: 'FileUpload',
dataType: 'json',
data: {
Name: $('#Name').val(), //you can declare the other form elements here
},
success: function (data, status) {
if (typeof (data.error) != 'undefined') {
if (data.error != '') {
//alert(data.error);
} else {
//alert(data.msg);
}
}
},
error: function (data, status, e) {
//alert(e);
}
}
)
return false;
}
@using (Ajax.BeginForm("Upload", "File", new { }, new AjaxOptions { }, new { enctype = "multipart/form-data" }))
{
</script>
<table>
<tr>
<td class="label">
@Html.LabelFor(m => m.Name)
</td>
<td>
<div class="field_container">
@Html.TextBoxFor(m => m.Name)
</div>
</td>
</tr>
<tr>
<td class="label">
@Html.LabelFor(m => m.PathToAttachment)
</td>
<td>
<div class="field_container">
@Html.TextBoxFor(m => m.FileUpload, new { type = "file" })
</div>
</td>
</tr>
</table>
<input type="submit" value="OK">
}
public class FileController : Controller
{
//it should show index.cshtml view
public ActionResult Index() { return View(); }
//do nothing on form submit
[HttpPost]
public ActionResult AddAttachment(AttachmentModel model)
{
return Json(new { success = true });
}
//this is where the file gets save in the server
public ActionResult UploadAttachment(String Name, HttpPostedFile FileUpload)
{
if (FileUpload.ContentLength > 0)
{
var r = new Random();
var uploadPath = Server.MapPath("~/Uploads");
var filename = FileName.Replace("_", "");
var savedFileName = Path.Combine(uploadPath, Path.GetFileName(filename));
//now you have your file
}
return new EmptyResult();
}
}