I have a small application that most of the time have an action behind a Start-button that should be triggered from the commandline parameter /AUTORUN. If that parameter is missing the user could also press it manually.
My question is where should I place this check for commandline so when it is given the GUI is still updated. The current solution is this, but the GUI is not updated until the action is finished.
procedure TfrmMainForm.FormShow(Sender: TObject);
begin
if FindCmdLineSwitch('AUTORUN') then
btnStart.Click;
end;
Post yourself a message from your OnShow
event handler. This will be processed as soon as your application starts servicing its message queue. That only happens when the application is ready to receive input. Which matches your my understanding of your requirements.
const
WM_STARTUP = WM_USER;
....
procedure TfrmMainForm.FormShow(Sender: TObject);
begin
PostMessage(Handle, WM_STARTUP, 0, 0);
OnShow := nil;//only ever post the message once
end;
Add a message handler to deal with the message:
procedure WMStartup(var Msg: TMessage); message WM_STARTUP;
You'd implement that like this:
procedure TfrmMainForm.WMStartup(var Msg: TMessage);
begin
inherited;
if FindCmdLineSwitch('AUTORUN') then
btnStart.Click;
end;
In the FormShow post yourself a message. In the message handler run your btnStart.
TfrmMainForm = class(TForm)
// snip
private
procedure AutoStart(var Message: TMessage); message wm_user;
// snip
end
procedure TfrmMainForm.FormShow(Sender: TObject);
begin
if FindCmdLineSwitch('AUTORUN') then
PostMessage(Handle, wm_user, 0, 0);
end;
procedure TfrmMainForm.AutoStart(var Message: TMessage);
begin
btnStart.Click;
end;
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