how to display barcode generate

private void GenerateBacode(string _data, string _filename)
{
    Linear barcode = new Linear();
    barcode.Type = BarcodeType.CODE11;
    barcode.Data = _data;
    barcode.drawBarcode(_filename);
}
private void GenerateQrcode(string _data, string _filename)
{
    QRCode qrcode = new QRCode();
    qrcode.Data = _data;
    qrcode.DataMode = QRCodeDataMode.Byte;
    qrcode.UOM = UnitOfMeasure.PIXEL;
    qrcode.X = 3;
    qrcode.LeftMargin = 0;
    qrcode.RightMargin = 0;
    qrcode.TopMargin = 0;
    qrcode.BottomMargin = 0;
    qrcode.Resolution = 72;
    qrcode.Rotate = Rotate.Rotate0;
    qrcode.ImageFormat = ImageFormat.Gif;
    qrcode.drawBarcode(_filename);
}