Question

I have an html file in my asp.net webforms project that people can download when clicking a button.

I would like to generate some <select> lists and append to certain parts of the html based on some database values before the file gets sent to the user. Is this possible using c#? My current download functionality:

public void DownloadOfflineAuditSheetEditor(object s, EventArgs e)
{
    Response.AppendHeader("content-disposition", "attachment; filename=thefile.html");
    Response.WriteFile(Server.MapPath("~/thefile.html"), true);
    Response.End();
}

Answer 1

Yes – you’d have to manipulate “the file” before it gets sent to the user.

In your method DownloadOfflineAuditSheetEditor you could have call a new method that reads the current file, gets the contents from the DB and then writes to the file or a new file, for example:

public void GenerateRealTimeContent() 
{

   var path = Server.MapPath("~/thefile.html");
   var dbContent = Database.GetContent(); // returns the <select> Options
   string[] lines = System.IO.File.ReadAllLines(path);
   StringBuilder sb = new StringBuilder();

   foreach (var line in lines) 
   {
     if (line == "CONTENT WHERE YOU WANT TO EDIT") 
     {
        SB.AppendLine(dbContent);
     }

     SB.AppendLine(line);
   }

  // code to write to your file

}

Then in your original function do:

public void DownloadOfflineAuditSheetEditor(object s, EventArgs e)
{
   GenerateRealTimeContent();
   Response.AppendHeader("content-disposition", "attachment; filename=thefile.html");
   Response.WriteFile(Server.MapPath("~/thefile.html"), true);
   Response.End();
}

http://msdn.microsoft.com/en-us/library/ezwyzy7b.aspx – Reading from a file

http://msdn.microsoft.com/en-us/library/aa287548(v=vs.71).aspx – Write to a file