CBFS Class

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The CBFS class gives applications the ability to create a virtual filesystem.

Syntax

cbfsconnect.Cbfs

Remarks

The CBFS class is used to create a virtual filesystem whose contents are stored and exposed in an application-defined manner. The CBFS class's unique and powerful event-based design gives applications the flexibility needed to support a wide range of use-cases, ranging from something as simple as translating filesystem calls to files and directories on another storage medium, to something as complex as generating the entire contents of the virtual filesystem on-the-fly based on some application-specific data source.

Getting Started

Each CBFS class instance controls a single virtual filesystem, and therefore a single virtual drive. Applications can use multiple instances of the CBFS class if their use-case requires the creation of multiple virtual drives; the class's Tag property can be used to distinguish between instances during event handlers.

Here's how to get up and running:

1. If the system driver hasn't been installed yet, call the Install method to do so. This only needs to be done once.
   • In production, the system driver can be installed (or updated) ahead-of-time by the application's installation script using the Installer DLL. Please refer to the Driver Installation topic for more information.
2. Call the Initialize method to initialize the CBFS class. This must be done each time the application starts (if the application is using multiple CBFS class instances, only the first instance created should be used to call Initialize).
3. Ensure that all of the necessary event handlers have been implemented. Some event handlers, such as OpenFile, ReadFile, GetFileInfo, EnumerateDirectory, etc; are mandatory and must be implemented by all applications (note that this is not an exhaustive list). Others are optional, and only need to be implemented when certain features are enabled. Please refer to the events' documentation for more information.
4. Create a virtual drive by calling the CreateStorage method.
5. Call the MountMedia method to "insert storage media" into the virtual drive. (This "media" can be changed at any time later using the UnmountMedia and MountMedia methods.)
6. Create one or more Mounting Points for the virtual drive using the AddMountingPoint method. A mounting point can be a drive letter, a UNC path, or a directory on an existing NTFS-formatted drive.
7. Later, the application can unmount the "media" from the virtual drive using the UnmountMedia method. At this point, the application could call the MountMedia method again to "insert different storage media".
8. To delete the virtual drive entirely, call the DeleteStorage method.
9. To uninstall the system driver, call the Uninstall method. This should not be done as part of the driver upgrade process.
   • In production, the system driver can be uninstalled by the application's uninstallation script using the Installer DLL. Please refer to the Driver Installation topic for more information.