Mar 16, 2014 04:52 AM|Mikesdotnetting|LINK
It's the RowDataBound event you need: http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.gridview.rowdatabound(v=vs.110).aspx
And you can use the File.WriteAllText method to create the file from the content once you have it. Then simply set the iframe src to the location of the file.
No, it won't open in a new window if you use an iframe.