procedure TForm1.Button1Click(Sender: TObject);
begin
Timer1.Enabled:=True;
MessageBox(Form1.Handle,'内容','标题',MB_SYSTEMMODAL);
end;
procedure TForm1.Timer1Timer(Sender: TObject);
var
WFound:THandle;
begin
Timer1.Enabled:=False;
WFound:=FindWindow(nil,'标题');
If WFound<>0 Then
SendMessage(WFound,WM_SYSCOMMAND,SC_CLOSE,0);
end;