Visual Basic .NET

Creating Callback function

The callback function has the following format. You can specify any name for this function.

Protected Sub CallBackProc(ByVal Id As Short, ByVal wParam As Integer, ByVal lParam As Integer, ByVal Param As IntPtr)

Using Delegate

In Visual Basic, please use delegate to handle a function pointer.
The delegate declarations for each callback routine are written in the CCAN.vb file.

Registering Callback function

Please use the following function to register callback function.

Flow of registering Callback function

- Initializing delegate
- Obtain GCHandle for interrupt handling delegate to prevent garbage collection
- Get the fixed pointer of the interrupt handler delegate
- Register the obtained fixed pointer using the callback function registration function CanNotifyEvent
- Release the GCHandle for the interrupt handling delegate when it is no longer needed (such as when the application ends)

For the details of coding, please refer to sample programs and Note of Using Visual Basic .NET.