Delphi

Question:
I want to make sure that my application was running only one time. But I dont know that my application already running or not. How?

Answer:
I have an example to detect delphi running or not. Surely you can use this (with little modification at function DelphiLoaded. You should try it.
Place it at form create and if your application detected running, you can close the new one. That way will avoid your application running twice.


function WindowExists(AppWindowName, AppClassName: string): Boolean;
var
hwd: LongWord;
begin
hwd := 0;
hwd := FindWindow(PChar(AppWindowName), PChar(AppClassName));
Result := False;
if not (Hwd = 0) then {window was found if not nil}
Result := True;
end;

function DelphiLoaded: Boolean;
begin
DelphiLoaded := False;
if WindowExists('TPropertyInspector', 'Object Inspector') then
if WindowExists('TMenuBuilder', 'Menu Designer') then
if WindowExists('TAppBuilder', '(AnyName)') then
if WindowExists('TApplication', 'Delphi') then
if WindowExists('TAlignPalette', 'Align') then
DelphiLoaded := True;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
if DelphiLoaded then
begin
ShowMessage('Delphi is running');
end;
end;


function DelphiIsRunning: Boolean;
begin
Result := DebugHook <> 0;
end;