生成图片式验证码试验

最新推荐文章于 2024-03-25 21:00:00 发布

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#random #object #structure #exception #session #fonts

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此博客展示了一段C#代码，用于绘制随机验证码图片。代码中创建了Bitmap对象，设置字体、随机数，将随机数绘制到图片上，最后保存图片到内存流并输出。同时还处理了可能出现的异常，给出了页面引用图片的示例。

share a simple way to generate a code for validation base on image.

in image.aspx.cs:

using System.Drawing;
using System.Drawing.Imaging;
private void Page_Load(object sender, System.EventArgs e)
{
drawimg();
}

private void drawimg()
{
   Bitmap newBitmap = new Bitmap(36,16,PixelFormat.Format32bppArgb);
   //draw image
   Graphics g = Graphics.FromImage(newBitmap);
   //fill the area with color
   g.FillRectangle(new SolidBrush(Color.White), new Rectangle(0,0,36,16));
   //set font object
   Font textFont = new Font("Verdana",9);
   //create RectangleF structure area
   RectangleF rectangle = new RectangleF(0,0,36,16);
   //set a random object
   Random rd = new Random();
   //get random number
   int valationNo = 1000 + rd.Next(8999);
   Session["valation"]=valationNo;
   //fill with color
   g.FillRectangle(new SolidBrush(Color.BurlyWood), rectangle);
   //fill with fonts
   g.DrawString(valationNo.ToString(), textFont, new SolidBrush(Color.Blue), rectangle);
   //save the image to memory stream
   try
   {
    System.IO.MemoryStream ms = new System.IO.MemoryStream();
    newBitmap.Save(ms,System.Drawing.Imaging.ImageFormat.Jpeg);
    Response.ClearContent();
    Response.ContentType = "image/Jpeg";
    Response.BinaryWrite(ms.ToArray());

    //newBitmap.Save(@"C:/Inetpub/wwwroot/test0401/VaImg.gif",ImageFormat.Gif); save it to harddisk
   }
   catch(Exception ex)
   {
    Response.Write(ex.Message);
   }

}

validate-page.aspx
...
<img src="image.aspx">
...

    //newBitmap.Save(@"C:/Inetpub/wwwroot/test0401/VaImg.gif",ImageFormat.Gif); save it to harddisk
   }
   catch(Exception ex)
   {
    Response.Write(ex.Message);
   }

}

validate-page.aspx
...
<img src="image.aspx">
...

validate-page.cs

private Boolean check()

{

if (Session["pcnum"] != null)

{

if (txtNumber.Text.Trim() == Session["valation"].ToString().Trim())

{

return true;

}

else