C＃ASP。 NET内联文件下载处理程序

Question

I'm trying to create a file handler for users to download files when their filenames are clicked on a web page. I've implemented this a few times without issues, but I'm currently getting an error which I can't get my head around.

Code:

protected void btnViewFile_Click(object sender, EventArgs e)
{
    var btnViewFile = sender as LinkButton;
    Response.Clear();
    Response.ContentType = "application/octet-stream";
    Response.AppendHeader("Content-Disposition", "attachment; filename=" + btnViewFile.CommandArgument.ToString());
    Response.WriteFile(Server.MapPath(btnViewFile.CommandArgument));
    Response.End();
}

If I look at the browser console, I can see:

Uncaught Sys.WebForms.PageRequestManagerParserErrorException: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed.

No exceptions appear to be thrown in the code, the requested file is converted into the correct full path; and I've tried quite a few different things - clearing headers manually, flushing before ending, giving a more explicit content-type header, using AddHeader instead of AppendHeader, using TransmitFile rather than WriteFile, and quite a bit more.

Any ideas?

Answer 1

In case anyone else comes across this situation, the problem was that I was registering it as a postback control in ScriptManager, not an async postback control.

D'oh!