The Microsoft Visio Software Development Kit contains the latest documentation, samples, header files, libraries, and tools that you need to develop custom solutions for Visio.
-Code Samples Library: Provides a database of reusable Visio code samples.
-Flowchart sample application: Shows how to create a Component Object Model (COM) add-in that automates the creation of a flowchart drawing from an Excel spreadsheet.
-TreeView sample application: Shows how to create a hierarchical drawing and its accompanying tree view in Visio.
-Office Plan sample application: Shows how you can use the Visio 2010 Drawing Control to create an application that takes advantage of the drawing features of Visio 2010 in a Microsoft Windows Form.
-VSTO Add-in sample application: Shows how to create an add-in, based on Microsoft Office development tools in Microsoft Visual Studio 2010, that includes custom Visio content and is deployed by using ClickOnce installation.