sometimes IEnumerable<HttpPostedFileBase> is null

[Tomas]

I am using MVC Telerik Upload and  while testing it I noticed that sometimes clientUpload is Null. I can't understand why some files are not uploaded though UploadFile  action is called. I have tried numerous time to reproduce this on Dev machine without any luck but some users on Prod server reproduce this bug. Maybe someone could point me where could be the problem?

The code is below (version 2012.2.607.340)

    @using (Html.BeginForm())
    {

  @(Html.Telerik().Upload()
           .Name("clientUpload")
           .Async(async => async
                               .Save("UploadFile", "File")
                               .Remove("Remove", "File")
                               .AutoUpload(false)
           )
           .ShowFileList(false)
           .Multiple(true)
           .ClientEvents(events => events
                                       .OnUpload("onUpload")



           )


          )
}

 function onUpload(e) {


        e.data = serializeForm();
}

function serializeForm() {
        var data = $("form").serializeArray();
        var formData = {};
        for (var i = 0; i < data.length; i++) {
            formData[data[i].name] = data[i].value;
        }

        return formData;
    }

        [HttpPost]        
        public ActionResult UploadFile(IEnumerable<HttpPostedFileBase> clientUpload, [OptionModelBinder]IOptionModel formData)
        {
           //sometimes clientUpload is null
        }

[T. Tsonev]

Hello,

Such problems are difficult to debug. Your best bet is to log the requests and try to spot a pattern in the failures. 

There are several approaches to logging. You can write your own HTTP module or use IIS failed request logging, to name just two of many.

I hope this helps.

Greetings,
Tsvetomir Tsonev
the Telerik team

[Tomas]

Thank you, I will try your recommended solutions. What I found so far is that ContentLength and TotalBytes do not match in request object. So it means the POST(upload) was interrupted but then why upload event in MVC app is fired? Also I found that this happens on Firefox.

Cache-Control=no-cache
Connection=keep-alive
Pragma=no-cache
Content-Length=4318072 (4.12 MB)
Content-Type=multipart/form-data; boundary=---------------------------265001916915724
Accept=text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding=gzip, deflate
Accept-Language=tr-tr,tr;q=0.8,en-us;q=0.5,en;q=0.3
Cookie=ASP.NET_SessionId=qoepkjemce41dervfpctm5xf; __utma=25844526.387102337.1343310072.1343310072.1343310072.1; __utmb=25844526.1.10.1343310072; __utmc=25844526; __utmz=25844526.1343310072.1.1.utmcsr=google|utmccn=(organic)|utmcmd=organic|utmctr=mdi%20pdf%20converter
User-Agent=Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20100101 Firefox/13.0.1
File=Zero elements found
Form=Zero elements found
AnonymousID=null
ApplicationPath=/
AppRelativeCurrentExecutionFilePath=~/File/UploadFile
ContentLength=4318072
ContentType=multipart/form-data; boundary=---------------------------265001916915724
CurrentExecutionFilePath=/File/UploadFile
CurrentExecutionFilePathExtension=
FilePath=/File/UploadFile
HttpMethod=POST
Path=/File/UploadFile
PathInfo=
RawUrl=/File/UploadFile
RequestType=POST
TotalBytes=982242
UserAgent=Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20100101 Firefox/13.0.1
UserHostAddress=78.187.28.43
UserHostName=78.187.28.43