Aspose.Diagram is a class library for working with MS Visio files. It is a pure .NET alternative for MS Visio Object Model. It enables developers to work with VSD and VDX files on ASP.NET Web applications, Web services, and desktop applications. It makes use of the advanced functionality of Visio's services to manipulate Visio documents on a server. A developer can open files and manipulate the elements of the diagram, from lines and fills to more complex elements, and then export to native Visio formats or XML.