Adding About Information

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The standard method for providing version and provider information within most applications that run on Windows platforms is the About menu selection item. MMC supports snap-in applications in providing this type of information. The information is displayed on a property page and is made available by using the ISnapinAbout interface.

The snap-in About information is only displayed in the Add/Remove Snap-in dialog box. Be aware that this information is not available to the user of a console file. Only the authors of saved console files can access the snap-in About information.

MMC also calls the snap-in ISnapinAbout implementation to obtain custom folder images for the snap-in static node. If a snap-in does not implement ISnapinAbout, MMC uses default folder images instead. Be aware that snap-ins can also programmatically specify the static node's folder images when the static node is selected and the snap-in receives an MMCN_EXPAND notification message. However, implementing ISnapinAbout is the recommended method for specifying the static folder images.

Methods belonging to ISnapinAbout include GetSnapinDescription, which provides text for the snap-in description box. GetProvider handles the name of the provider, and GetSnapinVersion obtains the snap-in version number. GetSnapinImage gets the main icon for the About property page, and GetStaticFolderImage gets the static folder images for the scope and result panes.

In the following procedure, be aware that {CLSID} and {snapinCLSID} indicate string representations of the specified CLSIDs. The strings must begin with an open brace ({) and end with a close brace (}).

To add About information

  1. Implement the ISnapinAbout interface in the snap-in.

  2. Use a COM object other than the snap-in's primary object (the one that exposes the snap-in's IComponentData interface) to expose the ISnapinAbout interface. This is so that, for performance reasons, MMC is not required to create an instance of the entire snap-in to access its About information.

  3. Register the CLSID of this object under the HKEY_CLASSES_ROOT\CLSID key in the {CLSID} subkey as an in-process server DLL. Also register an apartment threading model for the object. This allows the snap-in's ISnapinAbout interface to be marshaled by COM to MMC.

    For more information about the HKEY_CLASSES_ROOT\CLSID key, see CLSID Key. For more information and a code example, see Registering and Unregistering a Snap-in.

  4. Also register the CLSID of the object under the HKEY_LOCAL_MACHINE\Software\Microsoft\MMC\SnapIns\{snapinCLSID} key. Be aware that the {snapinCLSID} key is the string representation of the snap-in's CLSID. In the About named value of the {snapinCLSID} key, specify the string representation of the CLSID of the object. For more information about the SnapIns Key, see Registering and Unregistering a Snap-in.