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asp.net 验证码实现代码一例
来源: 互联网 发布时间:2014-08-30
本文导语: 需要新建一个创建验证码图片的页面ValidateCode.aspx,其后台cs文件代码如下: PageLoad private void Page_Load(object sender, System.EventArgs e) { string checkCode = CreateRandomCode(4); Session["CheckCode"] = checkCode; CreateImage(checkCode); } //CreateR...
需要新建一个创建验证码图片的页面ValidateCode.aspx,其后台cs文件代码如下:
PageLoad private void Page_Load(object sender, System.EventArgs e) { string checkCode = CreateRandomCode(4); Session["CheckCode"] = checkCode; CreateImage(checkCode); } //CreateRandomCode 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; } //CreateImage 用于生成图 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