Run JavaScript after an "Attachment Response" in ASP? - asp.net

Question

So here is my problem: I have a code that use response to ExportFile, but the problem is after the response code. the succeeding code no longer executes or it is like being read but ignored. sorry for being noob. so here is my code:
fullFilePath = "" + rootPath + "" + Filename + ".xlsx";
string fileName = fullFilePath.Substring(fullFilePath.LastIndexOf('\\') + 1);
byte[] buffer;
using (FileStream fileStream = new FileStream(fullFilePath, FileMode.Open))
{
int fileSize = (int)fileStream.Length;
buffer = new byte[fileSize];
// Read file into buffer
fileStream.Read(buffer, 0, (int)fileSize);
}
Response.Clear();
Response.Buffer = true;
Response.BufferOutput = true;
Response.ContentType = "application/x-download";
Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName);
Response.CacheControl = "public";
// writes buffer to OutputStream
Response.OutputStream.Write(buffer, 0, buffer.Length);
newFile.Delete();
ClientScript.RegisterStartupScript(GetType(), "id", "EnableCtrl()", true);
after this has been executed the javascript "EnableCtrl()" is not being fired or triggered. And when I delete the part of code which is related to response and change it to something else the javascript is being triggered. So how could i run a javascript after a response code?

Answer 1

The script won't/can't be triggered this method because the browser has already been sent the response: which is the file, and not the markup from a post-back. One request. One response. And it wasn't the post-back markup.
Instead, I would suggest either:
Handling the "Client Click" of the initiating control in the browser as well (the action could be delayed with setTimeout). Browser won't actually refresh the page/DOM because of the attachment disposition in the response, which is why this works. However, there are no client-side events for if a download was accepted, has started, or has completed1
Change the design so the "download" is a separate action with no other side-effect.
Happy coding.
1 It's possible to contrive server-assisted setups that allow the client to query the progress of a download, much like an upload progress indicator. However, this is not trivial or standard and may still not accurately reflect the state.