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Custom Document Properties Overview

Applies to

The information in this topic applies only to the specified Visual Studio Tools for Office projects and versions of Microsoft Office.

Project type

  • Document-level projects

Microsoft Office version

  • 2007 Microsoft Office system

  • Microsoft Office 2003

For more information, see Features Available by Application and Project Type.

When a document is part of a document-level customization, Visual Studio Tools for Office gives the document two custom properties: _AssemblyLocation and _AssemblyName. When a user opens a document, the Microsoft Office application checks for these custom document properties. If they exist in the document, the application loads the Visual Studio Tools for Office runtime, which starts the customization. For more information, see Architecture of Visual Studio Tools for Office Solutions.

The values of these properties depend on which version of Microsoft Office the solution is designed for:

  • _AssemblyName

    This property contains the CLSID of an interface in the Visual Studio Tools for Office loader. The CLSID value is 4E3C66D5-58D4-491E-A7D4-64AF99AF6E8B. You should never change this value.

  • _AssemblyLocation

    This property contains a string that provides details about the deployment manifest for the customization. For more information about manifests, see Application and Deployment Manifests in Office Solutions.

Format of the _AssemblyLocation Property

The_AssemblyLocation property value can have different formats, depending on how the solution is deployed:

  • If the solution is published to be installed from a Web site, UNC path, or a CD or USB drive, the _AssemblyLocation property has the format DeploymentManifestPath|SolutionID. The following string is an example:


  • If you are running or debugging the solution from Visual Studio, the _AssemblyLocation property has the format DeploymentManifestName|SolutionID|vstolocal. The following string is an example:


The SolutionID is a GUID that the Visual Studio Tools for Office runtime uses to identify the solution. The SolutionID is automatically generated when you build the project. The vstolocal term indicates to the Visual Studio Tools for Office runtime that the assembly should be loaded from the same folder as the document.

  • _AssemblyName

    This property contains an asterisk (*). This indicates to the Microsoft Office application that the document has a Visual Studio Tools for Office customization.

  • _AssemblyLocation

    This property contains the GUID of the Runtime Storage Control. For more information, see Runtime Storage Control Overview.