You can use the PAGENAME ShapeSheet function as follows:
Hyperlink.Row_1.Address ="mailto:TargetMailbox@mycompany.com?subject=Visio%20for%20Standards%20-Question/Comment%20"&PAGENAME()&"&cc=LoggedinUser@mycompany.com&body=I%20have%20a%20question.%0AI%20would%20like%20to%20know"