WM_INPUTLANGCHANGEREQUEST top-level constant
int
const WM_INPUTLANGCHANGEREQUEST
Posted to the window with the focus when the user chooses a new input language, either with the hotkey (specified in the Keyboard control panel application) or from the indicator on the system taskbar. An application can accept the change by passing the message to the DefWindowProc function or reject the change (and prevent it from taking place) by returning immediately.
Implementation
const WM_INPUTLANGCHANGEREQUEST = 0x0050;