Kendo upload error "An asynchronous module or handler completed while an asynchronous operation was still pending."

[xion]

Hi..

When I upload file using kendo upload, it will hit the error event with response message "An asynchronous module or handler completed while an asynchronous operation was still pending.", but the file is successfully uploaded.

This only happen on the first time, subsequently is not getting the error anymore.

$("#files").kendoUpload({
	async: {
		saveUrl: "upload.aspx",
		removeUrl: "remove",
		autoUpload: true,
		allowmultiple: true,
		batch: true
	},
	localization: {
		select: "Select Files"
	},
	complete: onComplete,                
	error: function (e) {
		console.log(e);
	},
	select: function (e) {
		
	},
	dropZone: "#dropZoneElement",
	showFileList: false
});

Any idea of what is going on?

[Martin]

Hello, 

The Upload configuration looks in order to me. Probably the issue is on the server method you are using for saveUrl. I am sharing two links that discuss the same error, I hope they will be helpful.

https://stackoverflow.com/questions/28805796/asp-net-controller-an-asynchronous-module-or-handler-completed-while-an-asynchr

https://social.msdn.microsoft.com/Forums/en-US/864bb0c6-7eee-4891-8a82-d699c79b604a/an-asynchronous-module-or-handler-completed-while-an-asynchronous-operation-was-still-pending?forum=aspwebforms

Regards,
Martin
Progress Telerik

[xion]

Hi..I have check the server method and is a very straight forward function that saving the uploaded file to a temporary folder.

private void uploadfile(){
   //there is no async/await/Task in this function
   for (int i = 0; i < Request.Files.Count; i++)
   {
        HttpPostedFile postedFile = Request.Files[i];
        postedFile.SaveAs(temp);
   }
}

[Martin]

Could you please trying with a server implementation similar to the one shown on our demos?