if (!string.IsNullOrEmpty(imageCode))            {                byte[] bytes = Convert.FromBase64String(imageCode);                MemoryStream s = new MemoryStream(bytes, true);                s.Write(bytes, 0, bytes.Length);                Image a = new Bitmap(s);                Bitmap bit = new Bitmap(this.pictureBox.Width, this.pictureBox.Height);                Graphics g = Graphics.FromImage(bit);//从指定的 Image 创建新的 Graphics(绘图)。                g.DrawImage(a, new Rectangle(0, 0, bit.Width, bit.Height), new Rectangle(0, 0, a.Width, a.Height), GraphicsUnit.Pixel);                this.pictureBox.Image = bit;            }