Visual Basic Concepts
Project File Formats
Microsoft Visual Basic utilizes and creates a number of files at both design and run time. Which files will be required by your project or application depends upon its scope and functionality.
Project File Extensions
Visual Basic produces a number of files when you create and compile a project. These can be categorized as follows: design-time, miscellaneous development, and run-time.
Design time files are the building blocks of your project: basic modules (.bas) and form modules (.frm), for example.
Miscellaneous files are produced by various processes and functions of the Visual Basic development environment: Package and Deployment Wizard dependency files (.dep), for example.
Design-time and Miscellaneous Files
The following table lists all the design-time and miscellaneous other files that may be produced when you develop an application:
| Extension | Description |
| .bas | Basic module |
| .cls | Class module |
| .ctl | User Control file |
| .ctx | User Control binary file |
| .dca | Active Designer cache |
| .ddf | Package and Deployment Wizard CAB information file |
| .dep | Package and Deployment Wizard dependency file |
| .dob | ActiveX document form file |
| .dox | ActiveX document binary form file |
| .dsr | Active Designer file |
| .dsx | Active Designer binary file |
| .dws | Deployment wizard script file |
| .frm | Form file |
| .frx | Binary form file |
| .log | Log file for load errors |
| .oca | Control TypeLib cache file |
| .pag | Property page file |
| .pgx | Binary property page file |
| .res | Resource file |
| .tlb | Remote Automation TypeLib file |
| .vbg | Visual Basic group project file |
| .vbl | Control licensing file |
| .vbp | Visual Basic project file |
| .vbr | Remote Automation registration file |
| .vbw | Visual Basic project workspace file |
| .vbz | Wizard launch file |
| .wct | WebClass HTML template |
Run-Time Files
When you compile your application, all the necessary design-time files are included in the run-time executable files. Run-time files are listed in the following table:
| Extension | Description |
| .dll | In-process ActiveX component |
| .exe | Executable file or ActiveX component |
| .ocx | ActiveX control |
| .vbd | ActiveX document state file |
| .wct | WebClass HTML template |