How display a json error message? - json.net

Question

I cannot display the Json message, Im trying prevente that user upload files with same name this is my controller code:
//POST: /Quote/Create Save the Uploaded file
public ActionResult SaveUploadedFile(int? chunk, string name)
{
bool exists;
var fileUpload = Request.Files[0];
var uploadPath = "C:\\Files";
chunk = chunk ?? 0;
if (System.IO.File.Exists(Path.Combine(uploadPath, name)))
{
exists = true;
}
else {
exists = false;
}
if (!exists)
{
using (var fs = new FileStream(Path.Combine(uploadPath, name), chunk == 0 ? FileMode.Create : FileMode.Append))
{
var buffer = new byte[fileUpload.InputStream.Length];
fileUpload.InputStream.Read(buffer, 0, buffer.Length);
fs.Write(buffer, 0, buffer.Length);
}
return Json(new { success = true }, JsonRequestBehavior.AllowGet);
}
else {
return Json(new { success = false, Message = "The file" + name +"already exists" }, JsonRequestBehavior.AllowGet);
}
}
This is my view code, if files success is false, then display the Json message:
UploadComplete: function (up, files) {
if (!files.success) {
alert(files.Message);
console.log(up);
} else {
var j = 0;
if (count > 0) {
j = count;
} else {
j = #i + '';
}
$.each(files, function (i, file) {
var extension = file.name.split(".");
$('.files').append('<input type=\"hidden\" name=\"Files[' + j + '].Name\" value=\"' + file.name + '\" />');
$('.files').append('<input type=\"hidden\" name=\"Files[' + j + '].Date\" value=\"' + "#DateTime.Now" + '\" />');
j++;
});
}
}
Thanks in advance !!

Answer 1

It seems that you need to be returning a string result rather than an ActionResult, since all you really want is if it passed or not. Also shortened your code a little to reflect the changes.
If you did want to return an object (meaning you wanted more than one property), I would create a model (class and then object), then return JsonResult rather than ActionResult.
Good documentation on how to return JsonResult object
C#
public string SaveUploadedFile(int? chunk, string name)
{
bool exists = false;
var fileUpload = Request.Files[0];
var uploadPath = "C:\\Files";
chunk = chunk ?? 0;
exists = System.IO.File.Exists(Path.Combine(uploadPath, name));
if (!exists)
{
using (var fs = new FileStream(Path.Combine(uploadPath, name), chunk == 0 ? FileMode.Create : FileMode.Append))
{
var buffer = new byte[fileUpload.InputStream.Length];
fileUpload.InputStream.Read(buffer, 0, buffer.Length);
fs.Write(buffer, 0, buffer.Length);
}
}
return message = !exists ? string.Empty
: "The file" + name + " already exists";
}
Javascript
if (files.message != '') { // meaning "exists" is true
console.log(up);
} else {
......
......
}