Write to CSV file and export it?
In C# ASP.net, could someone show me how I can write entries from an Array/List to a CSV file on the server and then open the file? I think the second part would be something like - Response.Redirect("http://myserver.com/file.csv"), however not sure on how to write the file on the server.
Also if this page is accessed by many users, is it better to generate a new CSV file every time or overwrite the same file? Would there be any read/write/lock issues if both users try accessing the same CSV file etc.?
Update:
This is probably a silly question and I have searched on Google but I'm not able to find a definitive answer - how do you write a CSV file to the webserver and export it in C# ASP.net? I know how to generate it but I would like to save it to www.mysite.com/my.csv and then export it.
Answer
Rom, you're doing it wrong. You don't want to write files to disk so that IIS can serve them up. That adds security implications as well as increases complexity. All you really need to do is save the CSV directly to the response stream.
Here's the scenario: User wishes to download csv. User submits a form with details about the csv they want. You prepare the csv, then provide the user a URL to an aspx page which can be used to construct the csv file and write it to the response stream. The user clicks the link. The aspx page is blank; in the page codebehind you simply write the csv to the response stream and end it.
You can add the following to the (I believe this is correct) Load event:
string attachment = "attachment; filename=MyCsvLol.csv";
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.ClearHeaders();
HttpContext.Current.Response.ClearContent();
HttpContext.Current.Response.AddHeader("content-disposition", attachment);
HttpContext.Current.Response.ContentType = "text/csv";
HttpContext.Current.Response.AddHeader("Pragma", "public");
var sb = new StringBuilder();
foreach(var line in DataToExportToCSV)
sb.AppendLine(TransformDataLineIntoCsv(line));
HttpContext.Current.Response.Write(sb.ToString());
writing to the response stream code ganked from here.