Das Handle ist ungültig

[KodeZwerg]

Delphi-Quellcode:

function GetEnvVarValue(const VarName: string): string;
var
  BufSize: Integer;  // buffer size required for value
begin
  // Get required buffer size (inc. terminal #0)
  BufSize := GetEnvironmentVariable(PChar(VarName), nil, 0);
  if BufSize > 0 then
  begin
    // Read env var value into result string
    SetLength(Result, BufSize - 1);
    GetEnvironmentVariable(PChar(VarName),
      PChar(Result), BufSize);
  end
  else
    // No such environment variable
    Result := '';
end;

procedure TForm1.Button1(Sender: TObject);
begin
  ShowMessage(GetEnvVarValue('SystemRoot'));
end;

hoffe es hilft!

edit

Delphi-Quellcode:

function ExpandEnvironment(const strValue: string): string;
var
  chrResult: array[0..1023] of Char;
  wrdReturn: DWORD;
begin
  wrdReturn := ExpandEnvironmentStrings(PChar(strValue), chrResult, 1024);
  if wrdReturn = 0 then
    Result := strValue
  else 
  begin
    Result := Trim(chrResult);
  end;
end;