Started the work for Spinbox.OnChanged() on Windows with the edit control.

basicctrls_windows.c

@@ -210,3 +210,29 @@ HWND newUpDown(HWND prevUpDown, void *data)
 		xpanic("error subclassing Spinbox up-down control to give it its own event handler", GetLastError());
 	return hwnd;
 }
+
+static LRESULT CALLBACK spinboxEditSubProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR id, DWORD_PTR data)
+{
+	switch (uMsg) {
+	case msgCOMMAND:
+		if (HIWORD(wParam) == EN_CHANGE) {
+			spinboxEditChanged((void *) data);
+			return 0;
+		}
+		return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
+	case WM_NCDESTROY:
+		if ((*fv_RemoveWindowSubclass)(hwnd, spinboxEditSubProc, id) == FALSE)
+			xpanic("error removing Spinbox edit control subclass (which was for its own event handler)", GetLastError());
+		return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
+	default:
+		return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
+	}
+	xmissedmsg("Spinbox edit control", "spinboxEditSubProc()", uMsg);
+	return 0;		// unreached
+}
+
+void setSpinboxEditSubclass(HWND hwnd, void *data)
+{
+	if ((*fv_SetWindowSubclass)(hwnd, spinboxEditSubProc, 0, (DWORD_PTR) data) == FALSE)
+		xpanic("error subclassing Spinbox edit control to give it its own event handler", GetLastError());
+}

spinbox_windows.go

@@ -35,6 +35,7 @@ func newSpinbox(min int, max int) Spinbox {
 	s.max = max
 	s.value = s.min
 	s.remakeUpDown()
+	C.setSpinboxEditSubclass(s.hwndEdit, unsafe.Pointer(s))
 	return s
 }
 
@@ -73,6 +74,13 @@ func spinboxUpDownClicked(data unsafe.Pointer, nud *C.NMUPDOWN) {
 	s.changed.fire()
 }
 
+//export spinboxEditChanged
+func spinboxEditChanged(data unsafe.Pointer) {
+	s := (*spinbox)(unsafe.Pointer(data))
+	// TODO
+	s.changed.fire()
+}
+
 func (s *spinbox) setParent(p *controlParent) {
 	C.controlSetParent(s.hwndEdit, p.hwnd)
 	C.controlSetParent(s.hwndUpDown, p.hwnd)

winapi_windows.h

@@ -76,6 +76,7 @@ extern void textfieldSetAndShowInvalidBalloonTip(HWND, WCHAR *);
 extern void textfieldHideInvalidBalloonTip(HWND);
 extern void setGroupSubclass(HWND, void *);
 extern HWND newUpDown(HWND, void *);
+extern void setSpinboxEditSubclass(HWND, void *);
 
 // init_windows.c
 extern HINSTANCE hInstance;