Detect CTRL+A in a texbox - winapi

Question

I have a main window hwndMain and a multiline Edit textbox:
hwndEdit = CreateWindowEx(0, L"EDIT", NULL, WS_CHILD | WS_VISIBLE | ES_LEFT | ES_MULTILINE | ES_AUTOVSCROLL, 0, 0, 300, 200, hwndMain, 0, (HINSTANCE) GetWindowLong(hwndMain, GWL_HINSTANCE), NULL);
I use this to detect CTRL+A in the textbox (because strangely, it's not available out-of-the-box):
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_KEYDOWN:
{
if (wParam == VK_CONTROL) // something here missing for detecting "A"
{
SendMessage(hwndEdit, EM_SETSEL, 0, -1); // select all ; this code works on its own, tested
}
...
Unfortunately, nothing happens when I do CTRL+A or CTRL+B or CTRL+ anything.
What is wrong?
Note: Ok the code for detecting A is still missing (i still don't know how to do it), but the code here should work for any CTRL+key...

Answer 1

Just check for WM_KEYDOWN for A and than use GetKeyState
case WM_KEYDOWN:
{
if (wParam=='A' && (::GetKeyState(VK_CONTROL) & 0x8000)!=0)
{
SendMessage(hwndEdit, EM_SETSEL, 0, -1); // select all
}
Remember that WM_KEYDOWN is only sent to the window that has the focus and not to parent windows.

Answer 2

After you create all your windows:
hwndEdit = CreateWindowEx(.....)
...
//Subbclassing
SetWindowSubclass(hwndEdit, (SUBCLASSPROC)EditWndProc, 0, 1);
LRESULT CALLBACK EditWndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwrefData){
switch(message){ //handle the messages
case WM_KEYDOWN:
//your code
break;
default: //for messages that we don't deal with
return DefSubclassProc(hwnd, message, wParam, lParam);
}
return DefSubclassProc(hwnd, message, wParam, lParam);
}