Edit Visio files in ASP .Net pages

Dear experts
I have a application, which is used for Desk allocation in different floors. This uses a Visio file as Floor Layout. The layout will be filled with Desk Details, like Port #, IP address and other details, like if the desk is occuppied fully, it will be in Red Color, if it's occupied partially it will be in Orange Color and if the Desk is free, it will be in green color. If any user wants to occupy a particular desk, he will open the particular floor layout on the ASPX page, then the user will select the Desk by Port # and will edit the Visio by giving color to the desk with other details, like booked by, booked for, Project ID, Project Name, Reporting Manager, etc.

My trouble is, i am not able to edit the Visio file and it doesn't fire any even. Kindly suggest, what to be done in this regard.

Regards
VB_Learner