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Editorial Team
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Asked: 2026-06-16T04:17:03+00:00

I’m learning Win32 API. I’ve created an empty window and added an Edit box

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I’m learning Win32 API. I’ve created an empty window and added an Edit box in it to type some text. I can type a text in it, but can’t switch the keyboard language.

Shortcuts like Alt+Shift don’t work. If I click the language icon in the tray, it will pause for a few seconds, then it will open the list finally, but my window will become inactive, so the change won’t affect it.

I can make the language change happen if I do this:

  1. press Alt+Shift (or whatever the combination is)
  2. press Alt, Space

Step 2 will result, as usual, in the popping of the window menu at the left top, but simultaneously the step 1 will become actual too.

I guess, I’m not processing some kind of message, or creating the window wrong, but I can’t find what is it that is wrong. Here is the full code:

#include <windows.h>

// handle of the edit box
HWND testEditBox;

// shows a message
void showMessage( LPSTR message ){
    MessageBox( GetActiveWindow(), message, "", MB_OK );
}

// a simple window procedure
LRESULT CALLBACK windowProc( HWND window, UINT message, WPARAM wparam, LPARAM lparam )
{
    switch( message )
    {
        case WM_CLOSE:
            DestroyWindow( window );
            break;
        case WM_DESTROY:
            PostQuitMessage( 0 );
            break;
        default:
            return DefWindowProc( window, message, wparam, lparam );
    }
    return 0;
}

int WINAPI WinMain( HINSTANCE instance, HINSTANCE prevInstance, LPSTR commandLine, int showMode )
{
    // create window class
    WNDCLASS windowClass;
    windowClass.cbClsExtra = 0;
windowClass.cbWndExtra = 0;
windowClass.style = 0;
    windowClass.hInstance = instance;
    windowClass.hCursor = LoadCursor( NULL, IDC_ARROW );
    windowClass.hbrBackground = (HBRUSH)(COLOR_BTNFACE + 1);
    windowClass.hIcon = LoadIcon( NULL, IDI_APPLICATION );
    windowClass.lpszClassName = "testWindow";
    windowClass.lpfnWndProc = windowProc;

    if( !RegisterClass( &windowClass ) )
    {
        showMessage( "Some trouble, sir" );
        return GetLastError();
    }

    HWND window = CreateWindow
    (
        "testWindow",
        "Test Window",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT,
        400, 300,
        NULL, // no parent
        NULL, // no menu
        instance,
        NULL // no 'window-creation data'
    );

    if( !window ){
        showMessage( "Some trouble, sir" );
        return GetLastError();
    }

    ShowWindow( window, showMode );


    // add an EDIT box to our window
    testEditBox = CreateWindow
    (
        "EDIT",
        "input here",
        WS_CHILD,
        10, 10,
        200, 20,
        window,
        NULL,
        instance,
        NULL
    );
    ShowWindow( testEditBox, SW_SHOW );

    // start message loop
    MSG message;
    while( GetMessage( &message, window, 0, 0 ) > 0 )
    {
        TranslateMessage( &message );
        DispatchMessage( &message );
    }


    return message.wParam;
}
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1 Answer

  1. Editorial Team

    The problem lays in the line GetMessage( &message, window, 0, 0 ). You are receiving messages only for the window, not testEditBox, so some messages aren’t dispatched. The line should be like GetMessage(&message, NULL, 0, 0).

    These are the messages received by testEditBox in your application when I press and release Ctrl + Shift:

    WM_KEYDOWN nVirtKey:VK_CONTROL cRepeat:1 ScanCode:1D fExtended:0 fAltDown:0 fRepeat:0 fUp:0
WM_KEYDOWN nVirtKey:VK_SHIFT cRepeat:1 ScanCode:2A fExtended:0 fAltDown:0 fRepeat:0 fUp:0
WM_KEYUP nVirtKey:VK_SHIFT cRepeat:1 ScanCode:2A fExtended:0 fAltDown:0 fRepeat:1 fUp:1
WM_KEYUP nVirtKey:VK_CONTROL cRepeat:1 ScanCode:1D fExtended:0 fAltDown:0 fRepeat:1 fUp:1

    Compare them to the messages after the fix:

    WM_KEYDOWN nVirtKey:VK_CONTROL cRepeat:1 ScanCode:1D fExtended:0 fAltDown:0 fRepeat:0 fUp:0
WM_KEYDOWN nVirtKey:VK_SHIFT cRepeat:1 ScanCode:2A fExtended:0 fAltDown:0 fRepeat:0 fUp:0
WM_KEYUP nVirtKey:VK_SHIFT cRepeat:1 ScanCode:2A fExtended:0 fAltDown:0 fRepeat:1 fUp:1
WM_IME_NOTIFY dwCommand:IMN_CLOSESTATUSWINDOW dwData:00000000
WM_IME_NOTIFY dwCommand:IMN_OPENSTATUSWINDOW dwData:00000000
WM_INPUTLANGCHANGE charset:0 hkl:04090409 //this
WM_IME_NOTIFY dwCommand:IMN_SETCOMPOSITIONFONT dwData:00000000
WM_KEYUP nVirtKey:VK_CONTROL cRepeat:1 ScanCode:1D fExtended:0 fAltDown:0 fRepeat:1 fUp:1
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