复杂一点的验证码怎么实现，

[zxj2634]

有图片的那种
给点代码，最好

[zxj2634]

额，发错板块了，本来想发在asp.net的

[wuyq11]

http://topic.csdn.net/u/20090429/16/9aee7f0f-16cb-4c49-a789-903aa8143932.html

[sirzxj]

string strchar = "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,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 = strchar.Split(',');
string VNum = "";
int temp = -1;
Random rand = new Random();
for (int i = 1; i < n + 1; i++)
{
if (temp != -1)

{
rand = new Random(i*temp*unchecked((int)DateTime.Now.Ticks));
}
int t = rand.Next(61);
if (temp != -1 && temp == t)
return RamdomNum(n);
temp = t;
VNum += VcArray[t];
}
return VNum;