You can apply this attribute to assemblies, interfaces, classes, enumerations, structures, or delegates, although the [<topic://cpgrfTypeLibraryImporterTlbimpexe>] can apply it for you when it imports a type library.

The string passed to the attribute must be in a format that is an acceptable constructor argument for the type Guid. To avoid conflicts with the type Guid, use the long name System.Runtime.InteropServices.GuidAttribute explicitly. Only use an explicit GUID when a type must have a specific GUID. If the attribute is omitted, a GUID is assigned automatically.