function Tfrm_edecAusfuhrDeklaration.ValidEmail(const sValue: String): Boolean;
  function CheckAllowed(const sTemp: String): Boolean;
  var
      iFor: Integer;
    begin
      Result := False;
      for iFor := 1 to Length(sTemp) do
      begin
        if not (sTemp[iFor] in ['a'..'z','A'..'Z','0'..'9','_','-','.']) then
        begin
          Exit;
        end;
      end;
      Result := True;
    end;

var
  iPos: integer;
  NamePart, ServerPart: string;
begin
  Result := False;
  iPos := Pos('@', sValue);
  if (iPos = 0) or (Pos('..', sValue) > 0) then
  begin
    Exit;
  end;
  NamePart := Copy(sValue, 1, iPos - 1);
  ServerPart := Copy(sValue, iPos +1, Length(sValue));
  if (Length(NamePart) = 0) or ((Length(ServerPart) < 4)) then
  begin
    Exit;
  end;
  iPos := Pos('.', ServerPart);
  if (iPos = 0) or (iPos >= (Length(ServerPart) - 1)) then
  begin
    Exit;
  end;
  //Result := CheckAllowed(NamePart) and CheckAllowed(ServerPart);
  Result := True;
end;