c# 生成验证码的一个例子
本文导语: 创建验证码图片的页面 ValidateCode.aspx。 后台cs代码如下所示: 代码示例: private void Page_Load(object sender, System.EventArgs e) { string checkCode = CreateRandomCode(4); Session["CheckCode"] = checkCode; CreateImage(checkCode); } //参数代表验证码位数 p...
创建验证码图片的页面 ValidateCode.aspx。
后台cs代码如下所示:
private void Page_Load(object sender, System.EventArgs e)
{
string checkCode = CreateRandomCode(4);
Session["CheckCode"] = checkCode;
CreateImage(checkCode);
}
//参数代表验证码位数
private string CreateRandomCode(int codeCount)
{
string allChar = "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,W,X,Y,Z";
string[] allCharArray = allChar.Split(',');
string randomCode = "";
int temp = -1; Random rand = new Random();
for (int i = 0; i < codeCount; i++)
{
if (temp != -1)
{
rand = new Random(i * temp * ((int)DateTime.Now.Ticks));
}
int t = rand.Next(35);
if (temp == t)
{
return CreateRandomCode(codeCount);
}
temp = t;
randomCode += allCharArray[t];
}
return randomCode;
}
//用于生成图的函数
private void CreateImage(string checkCode)
{
int iwidth = (int)(checkCode.Length * 11.5);
System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 20);
Graphics g = Graphics.FromImage(image);
Font f = new System.Drawing.Font("Arial", 10, System.Drawing.FontStyle.Bold);
Brush b = new System.Drawing.SolidBrush(Color.White);
//g.FillRectangle(new System.Drawing.SolidBrush(Color.Blue),0,0,image.Width, image.Height);
g.Clear(Color.Blue);
g.DrawString(checkCode, f, b, 3, 3);
Pen blackPen = new Pen(Color.Black, 0);
Random rand = new Random();
for (int i=0;i