Files with .VSSM extension are Microsoft Visio Stencil files that support provide support for macros. A VSSM file when opened allows to run the macros to achieve desired formatting and placement of shapes in a diagram. Learn more about this file format here.

public static readonly DiagramFileType Vssm

Public Shared ReadOnly Vssm As DiagramFileType

public:
static initonly DiagramFileType^ Vssm

static val Vssm: DiagramFileType