Xceed Zip Compression Library Documentation
DLL API Event handling by Windows messages
Direct DLL API > DLL API Event handling by Windows messages

Event notification by window messages can be selected by calling the XzSetXceedZipWindow function with a handle to the window that is to receive the special WM_USER_XCEEDZIPEVENT message (WM_USER + 1555), defined in XceedZipAPI.h

With this notification method, the specified window will receive the WM_USER_XCEEDZIPEVENT message every time an event is triggered. The WM_USER_XCEEDZIPEVENT message's WPARAM parameter will contain the event index number, and the LPARAM parameter a pointer to the correct parameter structure. Depending on the value of the WPARAM parameter, you should typecast the LPARAM parameter to the correct structure pointer.