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IManagedAddin interface

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Implement the IManagedAddin interface to create a component that loads managed VSTO Add-ins. This interface was added in the 2007 Microsoft Office system.

Syntax

[
    object,
    uuid(B9CEAB65-331C-4713-8410-DDDAF8EC191A),
    pointer_default(unique),
    oleautomation
]
interface IManagedAddin : IUnknown
{
    HRESULT Load(
        [in] BSTR bstrManifestURL,
        [in] IDispatch *pdispApplication);
    HRESULT Unload();
};

Methods

The following table lists the methods that are defined by the IManagedAddin interface.

Name Description
IManagedAddin::Load Called when a Microsoft Office application loads a managed VSTO Add-in.
IManagedAddin::Unload Called just before a Microsoft Office application unloads a managed VSTO Add-in.

Remarks

Microsoft Office applications, starting with the 2007 Microsoft Office system, use the IManagedAddin interface to help load Office VSTO Add-ins. You can implement the IManagedAddin interface to create your own VSTO Add-in loader and runtime for managed VSTO Add-ins, instead of using the VSTO Add-in loader (VSTOLoader.dll) and Visual Studio Tools for Office runtime . For more information, see Architecture of VSTO Add-ins.

How managed Add-ins are loaded

The following steps occur when an application starts:

  1. The application discovers VSTO Add-ins by looking for entries under the following registry key:

    HKEY_CURRENT_USER\Software\Microsoft\Office\<application name>\Addins\

    Each entry under this registry key is a unique ID of the VSTO Add-in. Typically, this is the name of the VSTO Add-in assembly.

  2. The application looks for a Manifest entry under the entry for each VSTO Add-in.

    Managed VSTO Add-ins can store the full path of a manifest in the Manifest entry under HKEY_CURRENT_USER\Software\Microsoft\Office\<application name>\Addins\<add-in ID>. A manifest is a file (typically, an XML file) that provides information that is used to help load the VSTO Add-in.

  3. If the application finds a Manifest entry, the application tries to load a managed VSTO Add-in loader component. The application does this by trying to create a COM object that implements the IManagedAddin interface.

    The Visual Studio Tools for Office runtime includes a VSTO Add-in loader component (VSTOLoader.dll), or you can create your own by implementing the IManagedAddin interface.

  4. The application calls the IManagedAddin::Load method and passes in the value of the Manifest entry.

  5. The IManagedAddin::Load method performs tasks required to load the VSTO Add-in, such as configuring the application domain and security policy for the VSTO Add-in that is being loaded.

    For more information about the registry keys that Microsoft Office applications use to discover and load managed VSTO Add-ins, see Registry entries for VSTO Add-ins.

Guidance to implement IManagedAddin

If you implement IManagedAddin, you must register the DLL that contains the implementation by using the following CLSID:

99D651D7-5F7C-470E-8A3B-774D5D9536AC

Microsoft Office applications use this CLSID to create the COM object that implements IManagedAddin.

Caution

This CLSID is also used by VSTOLoader.dll in the Visual Studio Tools for Office runtime . Therefore, if you use IManagedAddin to create your own VSTO Add-in loader and runtime component, you cannot deploy your component to computers that are running VSTO Add-ins that rely on the Visual Studio Tools for Office runtime .

See also