How To Use Project and Binary Compatibility

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You can set the Project's Compatibility in the Project\Properties dialog box, under the Component tab.

Visual Basic has three different compatibility settings for Projects:

• No compatibility.
• Project compatibility.
• Binary compatibility.

No Compatibility

With this setting, no compatibility is enforced. Visual Basic creates new Interface IDs and Class IDs every time you build or compile your project. Each version built can only be used with applications created to work with that specific build of the component.

Project Compatibility

With this setting, you can make your project compatible to a specific component project. While new type library information is generated, the type library identifier is maintained so that test projects can still refer to the component project. This setting is for maintaining compatibility during testing. Therefore, once the component is released, it behaves the same as the No Compatibility setting.

Binary Compatibility

When you compile your project, Visual Basic only creates new Class and Interface IDs when necessary. It preserves the class and interface IDs from the previous version(s) so that programs compiled using an earlier version will continue to work. If you are making a change that will result in an incompatible version, Visual Basic will warn you. If you want to maintain compatibility with older, released versions of an ActiveX component, this is the setting you need to use.