Question:
How can I find the active child window (like the 'follow focus' option in WinSight). I know how to enumerate child windows, but I don't know how to detect if a child window is active (has the caret / focus).
Answer:
Use the procedure below. It will return the handle, class name and caption text through 3 var parameters.
procedure GetFocusedControl(var FocusWin: HWND; var ClassName, ControlText: string);
var
hOtherWin: HWND;
OtherThreadID: Cardinal;
aDwordvar: DWORD;
hFocusWin: HWND;
S,
ss: string;
I: Integer;
begin
S := '';
ss := '';
hFocusWin := -1;
hOtherWin := GetForegroundWindow;
OtherThreadID := GetWindowThreadProcessID(hOtherWin, @aDwordvar);
if AttachThreadInput(GetCurrentThreadID, OtherThreadID, True) then
begin
hFocusWin := GetFocus;
if hFocusWin<>0 then
try
I := SendMessage(hFocusWin, WM_GETTEXTLENGTH, 0, 0);
SetLength(S, I+1);
SendMessage(hFocusWin, WM_GETTEXT, I+1, Integer(PChar(S)));
SetLength(ss, 260);
GetClassName(hFocusWin, PChar(ss), 260);
finally
AttachThreadInput(GetCurrentThreadID, OtherThreadID, False);
end;
end;
FocusWin := hFocusWin;
ClassName := Trim(ss);
ControlText := Trim(S);
end;