[.NET] 生成驗證碼圖片

這是登入或發文時,常用的生成驗證碼圖片程式。
checkCode　是要生成圖片的亂數數字或英文

<ex> "2657" or "rfyj"

    public static void CreateImage(string checkCode)

    {

        int iwidth = (int)(checkCode.Length * 11);

        System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 18);

        Graphics g = Graphics.FromImage(image);

        Font f = new System.Drawing.Font("Arial", 12, System.Drawing.FontStyle.Bold);

        Brush b = new System.Drawing.SolidBrush(Color.Silver);

        //g.FillRectangle(new System.Drawing.SolidBrush(Color.Blue),0,0,image.Width, image.Height);

        g.Clear(Color.Indigo);

        g.DrawString(checkCode, f, b, 2, 0);

        Pen blackPen = new Pen(Color.Brown, 2);

        Random rand = new Random();

        System.IO.MemoryStream ms = new System.IO.MemoryStream();

        image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

        System.Web.HttpContext.Current.Response.ClearContent();

        System.Web.HttpContext.Current.Response.ContentType = "image/Jpeg";

        System.Web.HttpContext.Current.Response.BinaryWrite(ms.ToArray());

        g.Dispose();

        image.Dispose();

    }