I would like to create a text file for export/download, like a *.csv, from an ASP.NET application. I know about Response.TransmitFile, but I want to do this without creating
Oh, that is not bad. In your ASPX page's Page_Load do this:
Response.ContentType = "text/xml";
Response.ContentEncoding = System.Text.Encoding.UTF8;
Response.Write(/* your text goes here */);
The above is an example if your 'file' is xml, but it can be anything, from and excel file to a pdf. All you have to do is update the ContentType which you can lookup via Google or Live.