You can use something like this to get the selected cell (or rather range):
var range = Globals.ThisAddIn.Application.Selection as Range; var value = range.Value2; var address = range.Address[false, false, Excel.XlReferenceStyle.xlA1, Type.Missing, Type.Missing];
If only one cell is selected you will get the address like "A15", if you have multiple cells (range) selected you will get the whole range address like "L24:O34". Same with the values, in case of a range you will get a whole array returned.