CSV - export to Excel

Excel export from DatagridView

http://www.codeproject.com/Articles/30169/Excel-export-from-DatagridView

Exporting a DataGridView to Excel in .NET 2.0 (C# code)

http://www.codeproject.com/Articles/32224/Exporting-a-DataGridView-to-Excel-in-NET-2-0-C-cod

DataGridView Export to Excel

http://www.kodefuguru.com/post/2010/06/02/DataGridView-Export-to-Excel.aspx