This is typically accomplished by explicitly registering the available components in a configuration file.
This means that assuring that the components are correct becomes a maintenance issue, particularly if it is the end user and not the developer who is expected to do the updating.
This approach solves the problems discussed in the previous section.
Because MEF parts declaratively specify their capabilities, they are discoverable at runtime, which means an application can make use of parts without either hard-coded references or fragile configuration files.
Using MEF, you will be able to add new operators without changing the application code. In Visual Basic, add the , which contains all the parts available and performs composition.