asp.net生成验证码

登陆时验证码的制作（asp.net）

1、显示样式：



2.新建一个页，Default2.aspx

3.在Page_load事件拷入如下代码

stringtmp = RndNum(4);

HttpCookiea =newHttpCookie("ImageV ", tmp);

Response.Cookies.Add(a);

this.ValidateCode(tmp);

4、在该页添加两个方法：

privatevoidValidateCode(stringVNum)

{

BitmapImg =null;

Graphicsg =null;

MemoryStreamms =null;

intgheight = VNum.Length * 12;

Img =newBitmap(gheight, 25);

g =Graphics.FromImage(Img);

//生¦¨²成¨¦随?机¨²生¦¨²成¨¦器¡Â

Randomrandom =newRandom();

//背À3景¡ã颜?色¦?

g.Clear(Color.Orange);

//for (int i = 0; i < 25; i++)

//{

// int x1 = random.Next(Img.Width);

// int x2 = random.Next(Img.Width);

// int y1 = random.Next(Img.Height);

// int y2 = random.Next(Img.Height);

// g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);

//}

//画-图ª?片?的Ì?前¡ã景¡ã噪?音°?点Ì?

for(inti = 0; i < 100; i++)

{

intx = random.Next(Img.Width);

inty = random.Next(Img.Height);

Img.SetPixel(x, y,Color.FromArgb(random.Next()));

}

//文?字Á?字Á?体¬?

Fontf =newFont("Arial Black ", 12);

// 文?字Á?颜?色¦?

SolidBrushs =newSolidBrush(Color.White);

g.DrawString(VNum, f, s, 3, 3);

ms =newMemoryStream();

Img.Save(ms, ImageFormat.Jpeg);

Response.ClearContent();

Response.ContentType ="image/Jpeg ";

Response.BinaryWrite(ms.ToArray());

g.Dispose();

Img.Dispose();

Response.End();

}

privatestringRndNum(intVcodeNum)

{

stringVchar ="0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p "+

",q,r,s,t,u,v,w,x,y,z";

string[] VcArray = Vchar.Split(newChar[] {','});

stringVNum =" ";

inttemp = -1;

Randomrand =newRandom();

for(inti = 1; i < VcodeNum + 1; i++)

{

if(temp != -1)

{

rand =newRandom(i * temp *unchecked((int)DateTime.Now.Ticks));

}

intt = rand.Next(35);

if(temp != -1 && temp == t)

{

returnRndNum(VcodeNum);

}

temp = t;

VNum += VcArray[t];

}

returnVNum;

}

5、在建立一个页面用来显示验证码：

则在该页面添加一个图片控件

6、在该页的Page_load事件中添加

ImageButton1.ImageUrl ="Default2.aspx";

7.前台页面添加：

<asp:ImageButtonID="ImageButton1"runat="server"Width="100"Height="30"/>

看不清？<ahref="javascript:changeCode()"style="text-decoration: underline;">换一张</a>

<scripttype="text/javascript">

functionchangeCode() {

document.getElementById('ImageButton1').src = document.getElementById('ImageButton1').src +'?';

}

</script>

这样就完成啦！