type
 TForm1 = class(TForm)
   Button1: TButton;
   procedure Button1Click(Sender: TObject);
 private
   { Private declarations }
 public
   { Public declarations }
 end;

 MyVariant = record
 private
   Data: Variant;
 public
   class operator Implicit(Value: MyVariant): Variant;
   class operator Implicit(Value: Variant): MyVariant;
   class operator Implicit(Value: MyVariant): Integer;
   class operator Implicit(Value: MyVariant): string;
 end;

var
 Form1: TForm1;

implementation

{$R *.dfm}

class operator MyVariant.Implicit(Value: MyVariant): Variant;
begin
 Result := Value.Data;
end;

class operator MyVariant.Implicit(Value: Variant): MyVariant;
begin
 Result.Data := Value
end;

class operator MyVariant.Implicit(Value: MyVariant): Integer;
begin
 if VarToStr(Value.Data) = '3G' then
   Result := 300
 else
 if VarToStr(Value.Data) = 'АБВ' then
   Result := 0
 else
   Result := StrToIntDef(VarToStrDef(Value.Data, '0'), 0);
end;

class operator MyVariant.Implicit(Value: MyVariant): string;
begin
 Result := VarToStr(Value.Data);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
 MV: MyVariant;
begin
 MV := '3G';
 ShowMessage(MV);
 Self.Left := MV;
end;