嘿嘿长跟给我 的,自己要努力学习一下了呵呵
private string validata()
{
Bitmap objBitMap = new Bitmap(60, 40);
Graphics objGraphics;
objGraphics = Graphics.FromImage(objBitMap);
objGraphics.Clear(Color.Teal);
Random k = new Random();
string Vchar = "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[] Vstr = Vchar.Split(",".ToCharArray());
int n1 = k.Next(0, 35);
int n2 = k.Next(0, 35);
int n3 = k.Next(0, 35);
int n4 = k.Next(0, 35);
string str1 = Vstr[n1].ToString();
string str2 = Vstr[n2].ToString();
string str3 = Vstr[n3].ToString();
string str4 = Vstr[n4].ToString();
string str = str1 + str2 + str3 + str4;
objGraphics.DrawString(str, new Font("宋体", 14), Brushes.Red, new PointF(5, 5));
string strAbsolutePath = (Server.MapPath(".")) + "//instructMap.gif";
objBitMap.Save(strAbsolutePath);
return str;
}