Function bind_raw_event_handler 

pub fn bind_raw_event_handler<F>(
    handle: &ControlHandle,
    handler_id: UINT_PTR,
    f: F,
) -> Result<RawEventHandler, NwgError>
where
    F: Fn(HWND, UINT, WPARAM, LPARAM) -> Option<LRESULT> + 'static,

Set a window subclass the uses the process_raw_events function of NWG. The subclass is only applied to the control itself and NOT the children.

When assigning multiple callback to the same control, a different id must be specified for each call or otherwise, the old callback will be replaced by the new one. See Label::hook_background_color for example.

Error:

• If the event handler with the same ID is already bound, this function will return an Error. The has_raw_handler method can be used to check this.

Panic:

• If the handle parameter is not a window-like control
• If the handler_id parameter is <= 0xFFFF

use native_windows_gui as nwg;

fn bind_raw_handler(window: &nwg::Window) -> nwg::RawEventHandler {
    const WM_MOVE: u32 = 3287542; // Not the actual value, but who cares?
    let handler_id = 0x10000;     // handler ids equal or smaller than 0xFFFF are reserved by NWG

    nwg::bind_raw_event_handler(&window.handle, handler_id, move |_hwnd, msg, _w, _l| {
        if msg == WM_MOVE {
            println!("MOVING!");
        }
        None
    }).unwrap()
}