Async upload triggers postback when a jpg is uploaded

[David J.]

Hi,

We are looking to asynchronously upload a file and temporarily store it in the AppData folder. The widget works perfectly when uploading pdf files, but for some reason it triggers a full postback when we try to upload a jpg file.

For context, here are some code snippets from the view and controller:

View

@(Html.Kendo().Upload().Name("uploadDocuments")
          .Async(a => a
              .Save("Upload", "Home")
              .AutoUpload(true)))

 

Controller

public ActionResult Upload(HttpPostedFileBase[] uploadDocuments)
        {
            foreach (var document in uploadDocuments)
            {
                var fileName = Path.GetFileName(document.FileName);
                var uploadPath = Server.MapPath("~/App_Data");
                var physicalPath = Path.Combine(uploadPath, fileName);
                document.SaveAs(physicalPath);
            }

            // Return an empty string to signify success
            return Content("");
        }

We're using Kendo for ASP .NET MVC version 2017.2.621. Any help is greatly appreciated.

Thanks!

[Ivan Danchev]

Hi David,

I am not sure I understand what you mean by "full postback" in the ASP.NET MVC context. In ASP.NET there are partial and full postbacks, while in ASP.NET MVC the post is to a specific controller, i.e. there is no concept of full and partial postbacks. So could you elaborate more on what exactly the difference in the behavior when uploading a .jpg file and a .pdf file consists of? In both cases the Upload action in the Home controller should be called.

Regards,
Ivan Danchev
Progress Telerik

[David J.]

Hi Ivan,

Sorry for the confusion. What I mean by a "full postback" is that the system behaves as if it refreshed the page completely. Similar to what would happen if I pressed "Enter" on the browser's address bar. When a pdf file is uploaded, the page behaves as expected. It saves the file to AppData and the upload widget shows that the file was uploaded successfully. However, when a jpg is uploaded the file is saved to AppData normally, but the page resets completely.

If it helps, I have a simplified solution on which I was able to reproduce the issue.

Thanks again!

 

[Ivan Danchev]

Hi David,

Thank you for explaining in more detail the behavior you are experiencing. I tried to reproduce it in a sample project, but to no avail: the page did not refresh regardless of uploading a pdf or a jpg file. If you have a sample project that demonstrates the issue could you please attach it, so we can take a closer look at what could be causing the different behavior at yours and at our end.

Regards,
Ivan Danchev
Progress Telerik

[David J.]

Hi Ivan,

Thank you for your attention.The solution was too large to upload in the forum, so here's a link to download it:

...

Thanks again.

[Ivan Danchev]

Hello David,

Thank you for attaching a sample project. We will review it and get back to you with new information.

On a separate note, when attaching/posting links to sample project in the forum please make sure to include only trial .dll files in it, or to remove the licensed .dll files. A licensed version of the Kendo.Mvc.dll was included in the project you linked in your last reply, which is why I edited your post and removed it.

Regards,
Ivan Danchev
Progress Telerik

[Ivan Danchev]

Hi David,

We checked the Upload's behavior in the project you attached, but once again we were not able to reproduce the described page refreshing. I recorded a short screencast showing how .jpg and .pdf files are uploaded without refreshing the page. Note that I added a simple input above the Upload and I type in random characters in it prior to uploading, as it is a good indication of the page being refreshed: when this happens the input loses its value. Please share any additional steps we need to follow in order to reproduce the issue.

Regards,
Ivan Danchev
Progress Telerik