Visio object model overview
Applies to: 
Visual Studio 
Visual Studio for Mac
Note
This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here
To develop Office solutions for Microsoft Office Visio, you can interact with the Visio object model. This object model consists of classes and interfaces that are provided in the primary interop assembly for Visio, and are defined in the Microsoft.Office.Interop.Visio namespace.
This topic provides a brief overview of the Visio object model. For information about using the Visio object model to perform tasks in Office projects, see the following topics:
Understand the Visio object model
Visio provides many objects with which you can interact. These objects are organized in a hierarchy that closely follows the user interface. At the top of the hierarchy is the Microsoft.Office.Interop.Visio.Application object. This object represents the current instance of Visio. The Microsoft.Office.Interop.Visio.Application object contains the Microsoft.Office.Interop.Visio.Document and Microsoft.Office.Interop.Visio.Page objects as well as the Microsoft.Office.Interop.Visio.Documents and Microsoft.Office.Interop.Visio.Pages collections. Each of these objects and collections has many methods and properties that you can access to manipulate and interact with it.
For more information, see the VBA reference documentation for Microsoft.Office.Interop.Visio.Application, Microsoft.Office.Interop.Visio.Document, and Microsoft.Office.Interop.Visio.Page objects, and also the Microsoft.Office.Interop.Visio.Documents and Microsoft.Office.Interop.Visio.Pages collections.
The following sections briefly describe the top-level objects and how they interact with each other. These objects include the following objects:
Application object
Document object
Page object
Application object
The Microsoft.Office.Interop.Visio.Application object represents the Visio application, and is the parent of all of the other objects. Its members usually apply to Visio as a whole. You can use the properties and methods of the Microsoft.Office.Interop.Visio.Application and the Microsoft.Office.Interop.Visio.ApplicationSettings objects to control the Visio environment.
In VSTO Add-in projects, you can access the Microsoft.Office.Interop.Visio.Application object by using the Application field of the ThisAddIn class. For more information, see Programming VSTO Add-Ins.
Document object
The Microsoft.Office.Interop.Visio.Document object is central to programming Visio. It represents a drawing, stencil, or template file. When you open a Visio document or create a new document, you create a new Microsoft.Office.Interop.Visio.Document object, which is added to the Microsoft.Office.Interop.Visio.Documents collection of the Microsoft.Office.Interop.Visio.Application object.
The document that has the focus is called the active document. It is represented by the Microsoft.Office.Interop.Visio.Application.ActiveDocument property of the Microsoft.Office.Interop.Visio.Application object.
Page object
The Microsoft.Office.Interop.Visio.Page object represents the drawing area of a foreground page or a background page. You can use the Microsoft.Office.Interop.Visio.Page.Background property to determine whether a page is a foreground or background page.
To create shapes, you can use methods that include the Microsoft.Office.Interop.Visio.Page.DrawSpline and Microsoft.Office.Interop.Visio.Page.DrawOval methods. Additionally, you can retrieve masters from stencils and place the shapes on a page by using the Microsoft.Office.Interop.Visio.Page.Drop or Microsoft.Office.Interop.Visio.Page.DropMany methods.
Use the Visio object model documentation
For complete information about the Visio object model, you can refer to the Visio VBA object model reference. The VBA object model reference documents the Visio object model as it is exposed to Visual Basic for Applications (VBA) code. For more information, see Visio object model reference.
All of the objects and members in the VBA object model reference correspond to types and members in the Visio primary interop assembly (PIA). For example, the Document object in the VBA object model reference corresponds to the Microsoft.Office.Interop.Visio.Document type in the Visio PIA. Although the VBA object model reference provides code examples for most properties, methods, and events, you must translate the VBA code in this reference to Visual Basic or Visual C# if you want to use them in a Visio VSTO Add-in project that you create by using Visual Studio.
Note
At this time, there is no reference documentation for the Visio primary interop assembly.
For related code samples and additional tools for creating Visio solutions, see Visio 2010 software development kit.
Additional types in primary interop assemblies
You can find types in the primary interop assemblies that are not visible to VBA because of implementation differences. VBA provides a view of the Visio object model that includes only the objects and members that you can use directly. The primary interop assemblies expose the same object model, but they also include other interfaces, classes, and members that translate objects in the COM object model to managed code. These additional items are not intended to be used directly in your code.
For more information, see Overview of classes and interfaces in the Office primary interop assemblies and Office primary interop assemblies.