I'm using this Delphi 7 code to detect if Internet Explorer is running:
function IERunning: Boolean;
begin
Result := FindWindow('IEFrame', NIL) > 0;
end;
This works on 99% of the systems with IE 8,9 and 10.
But there are some systems (unfortunately none of mine, but I have two beta testers which have such systems, both Win7 x64 SP1) where FindWindow() returns 0 for IEFrame, even if IE is in memory.
So I've coded an alternate method to find the window:
function IERunningEx: Boolean;
var WinHandle : HWND;
Name: array[0..255] of Char;
begin
Result := False; // assume no IE window is present
WinHandle := GetTopWindow(GetDesktopWindow);
while WinHandle <> 0 do // go thru the window list
begin
GetClassName(WinHandle, @Name[0], 255);
if (CompareText(string(Name), 'IEFrame') = 0) then
begin // IEFrame found
Result := True;
Exit;
end;
WinHandle := GetNextWindow(WinHandle, GW_HWNDNEXT);
end;
end;
The alternate method works on 100% of all systems.
My question - why is FindWindow() not reliable on some of the systems?
I'm guessing that FindWindow
is declared to return a WinHandle, which is a THandle, which is an Integer, which is signed. (At least, I think this was the case many years ago when I programmed in Delphi.)
If IE has a window handle with the top bit set then it will be negative so your test will return False:
Result := FindWindow('IEFrame', NIL) > 0;
Window handles don't usually have the top bit set, but I don't know that it's impossible.