在多个Inno设置脚本常量实例中重用相同(随机)值

function GenerateRandomString(Length: Integer): String;
var
  CharSet: String;
  I: Integer;
begin
  CharSet := 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
  Result := '';
  for I := 1 to Length do
  begin
    Result := Result + CharSet[Random(Length(CharSet)) + 1];
  end;
end;

[Code]
var
  RandomValue: String;

function InitializeSetup: Boolean;
begin
  RandomValue := GenerateRandomString(10);
  Result := True;
end;

[Setup]
AppName=MyApp
AppVersion=1.0
DefaultDirName={pf}\MyApp

[Files]
Source: "MyFile.txt"; DestDir: "{app}"; DestName: "{code:GetRandomFileName}"

[Code]
function GetRandomFileName(Param: String): String;
begin
  Result := RandomValue + '.txt';
end;