Umgebungsvariablen unter Vista ohne Admin-Rechte

[HPW]

Bislang habe ich mir Umgebungsvariablen so geholt:

Delphi-Quellcode:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls,
  Registry,
  Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Edit1   : TEdit;
    Edit2   : TEdit;
    Button1 : TButton;
    Label1  : TLabel;
    procedure Button1Click(Sender: TObject);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
  end;

Type
  tEnviromentOwner = (eoUser, eoSystem);

var
  Form1: TForm1;

Const
  cEnviromentOwnerRegPlace : Array [tEnviromentOwner] of Record
      Root: HKEY;
      Key: String
    End = (
      (Root: HKEY_CURRENT_USER;
       Key: 'Environment'),
      (Root: HKEY_LOCAL_MACHINE;
       Key: 'SYSTEM\CurrentControlSet\Control\Session Manager\Environment')
    );


implementation

{$R *.dfm}

Function GetSystemWideEnvironmentVariable (aOwner: tEnviromentOwner; aName: String): String;
Var
  Reg: TRegistry;
begin
  Reg := TRegistry.Create;
  With Reg, cEnviromentOwnerRegPlace [aOwner] Do
    Try
      RootKey := Root;
      OpenKey (Key, False);
      Result := ReadString (aName);
    Finally
      Free;
    End;
end;

Function GetEnv(regarea, varname : STRING ): String;
VAR
   retstr : String;
BEGIN
    IF AnsiUpperCase(regarea) = 'USER' THEN
      retstr := GetSystemWideEnvironmentVariable (eoUser, varname)
    ELSE IF AnsiUpperCase(regarea) = 'SYSTEM' THEN
      retstr := GetSystemWideEnvironmentVariable (eoSystem, varname)
    ELSE
      retstr := '';
    Result :=  retstr;
END;


procedure TForm1.Button1Click(Sender: TObject);
begin
  Label1.Caption :=  GetEnv( Edit1.Text , Edit2.Text  );
end;

end.

Als Standard-User unter Vista gibt dies nichts mehr zurück.
Das Test-Programm als Administrator gestartet liefert wie immer zurück.
Wie funktioniert das immer?

Grüsse,