When you develop an application that needs exporting capability for several type of files, you should use some internal or external programming libraries. I will mention a few useful and free libraries for our exporting purposes.

I don’t want to give much explanation about these libraries because you can find out easily If you want. My purpose is giving the summary (library name and basic code) about that.
Creating PDF File
Library: iTextSharp
Document <strong>document</strong> = new Document(); PdfWriter writer = PdfWriter.GetInstance(document, new System.IO.FileStream ("C:\\test.pdf", System.IO.FileMode.Create)); document.Open(); document.Add(Paragraph p1 = new Paragraph("Hello World");); document.Close();
Creating Word File
Library: Microsoft Word 14.0 Object Library (Internal)
Application app1 = new Application(); app1.Visible = true; _Document doc1 = app1.Documents.Add(); doc1.Words.First.InsertBefore("Hello World"); doc1.SaveAs2("C:\\test.docx");
Creating Excel File
Library: Microsoft Excel 14.0 Object Library (Internal)
_Application app = new Application(); _Workbook workbook = app.Workbooks.Add(Type.Missing); _Worksheet worksheet = null; app.Visible = true; worksheet = workbook.Sheets["Sheet1"]; worksheet = workbook.ActiveSheet; worksheet.Cells[1, 1] = "Hello World"; worksheet.Columns.AutoFit(); worksheet.Cells.HorizontalAlignment = Element.ALIGN_RIGHT; workbook.SaveAs("C:\\test.xls", Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, XlSaveAsAccessMode.xlExclusive, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
Creating Outlook Files (New Mail Window)
Library: Microsoft Outlook 14.0 Object Library (Internal)
Outlook.Application oApp = new Outlook.Application(); Outlook.MailItem oMsg = (Outlook.MailItem)<strong>oApp</strong>.CreateItem (Outlook.OlItemType.olMailItem); oMsg.HTMLBody = "Hello World"; oMsg.Display();
Creating Text Files
Library: System.IO (Internal)
System.IO.File.WriteAllText("C:\test.txt", "Hello World");
Notes
To open a file, use this code:
System.Diagnostics.Process.Start("test.pdf");
Before using any library (dll), do not forget to add it as a reference (Visual Studio > Solution Explorer > Right Click on References > Add Reference
):

Thanks for sharing!