Question

Is there a way to lock an Excel workbook in such a way that you cannot select any cells and/or change any of the workbook’s information? Basically when my program is in export mode, I don’t want the user to be able to change data or select any cells.

Answer 1

Maybe this way : Locking worksheets

Code snippet given by the MSDN :

Globals.Sheet1.Protect(getPasswordFromUser, 
missing, missing, missing, missing, missing, missing, missing, missing, 
missing, missing, missing, missing, true, missing, missing);

You should be able to do the same without using the Globals.Sheet1, because the MSDN assumes you have such a sheet. Doing it programatically should be possible.

Edit : Locking the Workbook itself, but you seem to want to lock both the WorkBook and the worksheet :
Workbook locking

this.Protect(getPasswordFromUser, missing, missing);

The password is optionnal :

The Protect and Unprotect methods allow you to protect a Microsoft Office Excel 2003 workbook so that users cannot add or delete worksheets, and to unprotect the workbook again. You can optionally specify a password, indicate whether you want the structure protected (so users cannot move sheets around), and indicate whether you want the workbook’s windows protected.

Protecting a workbook does not stop users from editing cells. To protect the data, you must protect the worksheets. For more information, see How to: Protect Worksheets.

here is another link Common tasks in Excel