When computer take order to shutdown , I need to save file - windows

Question

How I can save the content of Listbox to file When the computer shutting down or sleeping, or restarting ???
I use Delphi XE7 ,
I do save the file , and I have no problem with it !
but I want to save the file when computer shutting down .
update my code and Problem:
my problem which is , when my project run in the background the both events OnClose & OnDestroy dose not work!
If the project work normally "not in the background", the both event's is work fine!
I figure my problem , which is my project working in background process , i add this lines to do this Application.MainFormOnTaskbar := False; Application.ShowMainForm := False; If i make my project to run in back ground process the events onClose and onDestroy is definitely not work,
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
var
str :TStringList;
i : integer;
begin
str := TStringList.Create;
for i := 0 to ListBox1.Count-1 do
str.Add(ListBox1.Items.Strings[i]);
try
str.SaveToFile('D:\test1.txt', TEncoding.UTF8);
finally
str.Free;
end;
end;
procedure TForm1.FormDestroy(Sender: TObject);
var
str :TStringList;
i : integer;
begin
str := TStringList.Create;
for i := 0 to ListBox1.Count-1 do
str.Add(ListBox1.Items.Strings[i]);
try
str.SaveToFile('D:\test15.txt', TEncoding.UTF8);
finally
str.Free;
end;
end;

Answer 1

Handle the WM_ENDSESSION message and save your file there.
Catch the windows message like this:
private
procedure OnShutDown(var Msg: TMessage); message WM_ENDSESSION;
And here is your implementation
procedure TForm1.OnShutDown(var Msg: TMessage);
begin
//Save your file here.
end;