How to: Programmatically Add Shapes to a Visio Document
You can add shapes to a Microsoft Office Visio document by retrieving the masters from a stencil and dropping the shapes on the active page.
For more information, see the VBA reference documentation for the Microsoft.Office.Interop.Visio.Documents.Add method, Microsoft.Office.Interop.Visio.Application.ActivePage property, and Microsoft.Office.Interop.Visio.Page.Drop method.
To add shapes to a Visio document
With a document active, retrieve the masters from the Documents.Masters collection and drop the shapes on the active document. You can retrieve a master by using the index or master name.
The following code example creates a blank Visio document, and then opens it with the Basic Shapes stencil docked. The code then retrieves several shapes and drops them on the active page.