bgiGetDatePickerDay

Returns the day component (1-31) from a DatePicker control. Searches gizmoMap for gizmo ID using find(). If found, calls DateTime_GetSystemtime() to retrieve SYSTEMTIME structure. Returns st.wDay field. Returns 0 if gizmo not found.

This function retrieves the day-of-month value from a DatePicker control. DateTime_GetSystemtime is a Windows Common Controls macro wrapping DTM_GETSYSTEMTIME message. SYSTEMTIME.wDay field contains day (1-31). Returns 0 for invalid gizmo ID (not ideal - valid dates can be 0). Use after user selects date or to query current picker value. Common pattern: call all three getters (Day, Month, Year) to retrieve complete date.