Download File link stop working after cancelling the save file dialog

Question

I have developed a custom web part to display all the items in a certain document library following the next link:

http://geekswithblogs.net/JayantSharma/archive/2012/08/15/how-to-download-files-from-sharepoint-document-library-using-c.aspx

I've bound the "Link button"s in each repeater item to do the following:

protected void lbtn_download_Click(object sender, EventArgs e)
    {
        LinkButton btn = (LinkButton)sender;
        RepeaterItem ritem = (RepeaterItem)btn.Parent;
        string fileAbsUrl = ((HiddenField)ritem.FindControl("hf_fileName")).Value;
        InvokeDownload(fileAbsUrl);
    }

as shown above, I get the absolute file name from a hidden field in my RepeaterItem and then call the InvokeDownload method which follows the instructions provided in the link above.

Here's the code for the InvokeDownload method:

        void InvokeDownload(string fileName)
    {
        string ext = fileName.Split('.')[fileName.Split('.').Length - 1];
        string name = fileName.Split('/')[fileName.Split('/').Length - 1];
        string contentType = "";
        using (SPWeb web = SPContext.Current.Site.OpenWeb(SPContext.Current.Site.RootWeb.ID))
        {
            SPFile tempFile = web.GetFile(fileName);
            string relativePath = tempFile.ServerRelativeUrl;
            byte[] obj = (byte[])tempFile.OpenBinary();
            switch (ext)
            {
                case "htm":
                case "html":
                    contentType = "text/HTML";
                    break;
                case "doc":
                case "docx":
                case "rtf":
                    contentType = "Application/msword";
                    break;
                case "xls":
                case "xlsx":
                    contentType = "Application/x-msexcel";
                    break;
                case "pdf":
                    contentType = "application/pdf";
                    break;
                default:
                    contentType = "text/plain";
                    break;
            }

            Response.ClearContent();
            Response.ClearHeaders();

            Response.ContentType = contentType;
            Response.AppendHeader("Content-Disposition", "attachment; filename=" + name);
            //Response.TransmitFile(Server.MapPath(fileName));
            //Response.End();
            if (Response.IsClientConnected)
            {
                Response.BinaryWrite(obj);
            }
            Response.Flush();
            Response.Close();
        }
    }

When I click on the "download" linkButton it prompts me with the save file dialog which is OK so far but when I cancel that dialog and try to click on another item's download button nothing happens at all and no download is ever invoked..

Please, can anyone help?

Many thanks in advance.

Answer 1

SharePoint registers a JavaScript "on submit" handler. In this handler the global variable _spFormOnSubmitCalled is set to true. SharePoint uses this variable to check if a submit was executed and prevents any further submits. Since your "download postback" does not refresh the page this variable remains true. With the effect that that all other buttons stop working.

To fix this try following:

https://stackoverflow.com/questions/7749393/no-more-post-back-after-file-download-in-sharepoint