private void GetstringImg(string outstring, int with, int height, Color color)
    {
        Bitmap imgage = new Bitmap(with,height);
        Graphics g = Graphics.FromImage(imgage);
        Font font = new Font("宋体",12, FontStyle.Bold);
        SolidBrush brush = new SolidBrush(color);
        g.Clear(Color.White);
        StringFormat format = new StringFormat();
        g.DrawString(outstring, font, brush, 0,0,format);
        MemoryStream ms = new MemoryStream();
        imgage.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

        content.Response.ClearContent();
        content.Response.ContentType = "image/pjpeg";
        content.Response.BinaryWrite(ms.ToArray());
        
                
    }
调用：
GetstringImg("189.00",30,10,Color.Red);