【登陆页面后台】
/// <summary>
/// </summary>
/// <param name="verifyCode">验证码</param>
/// <returns></returns>
private bool yzVerifyCode(string verifyCode)
{
if (Session["CheckCode"] != null)
{
if (Session["CheckCode"].ToString().ToLower() == verifyCode.ToLower())
{
return true;
}
return false;
}
return false;
}
【前台】
<asp:TextBox id="tb_verifyCode" CssClass="tb_verifyCode" runat="server"
MaxLength="4" Width="48px"></asp:TextBox> <img id="img_verifyCode" alt="换一张" class="img_verifyCode" src="/ValidateCode.aspx" onclick="this.src='/ValidateCode.aspx?'+Math.random()" style="vertical-align: middle; margin-top:-3px;"/></span><asp:TextBox id="tb_verifyCode" CssClass="tb_verifyCode" runat="server"
【新页面验证码】
public partial class ValidateCode : System.Web.UI.Page
{
private void Page_Load(object sender, System.EventArgs e)
{
string checkCode = GetRandomCode(4);
Session["CheckCode"] = checkCode;
SetPageNoCache();
CreateImage(checkCode);
}
/// <summary>
/// 设置页面不被缓存
/// </summary>
private void SetPageNoCache()
{
Response.Buffer = true;
Response.ExpiresAbsolute = System.DateTime.Now.AddSeconds(-1);
Response.Expires = 0;
Response.CacheControl = "no-cache";
Response.AppendHeader("Pragma", "No-Cache");
}
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,M,N,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);//性能问题
}
temp = t;
randomCode += allCharArray[t];
}
return randomCode;
}
private string GetRandomCode(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,M,N,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(temp * i * ((int)DateTime.Now.Ticks));
}
int t = rand.Next(33);
while (temp == t)
{
t = rand.Next(33);
}
temp = t;
RandomCode += allCharArray[t];
}
return RandomCode;
}
private void CreateImage(string checkCode)
{
int iwidth = (int)(checkCode.Length * 14);
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.Black);
Brush r = new System.Drawing.SolidBrush(Color.FromArgb(166, 8, 8));
//g.FillRectangle(new System.Drawing.SolidBrush(Color.Blue),0,0,image.Width, image.Height);
// g.Clear(Color.AliceBlue);//背景色
g.Clear(System.Drawing.ColorTranslator.FromHtml("#99C1CB"));//背景色
char[] ch = checkCode.ToCharArray();
for (int i = 0; i < ch.Length; i++)
{
if (ch[i] >= '0' && ch[i] <= '9')
{
//数字用红色显示
g.DrawString(ch[i].ToString(), f, r, 3 + (i * 12), 3);
}
else
{ //字母用黑色显示
g.DrawString(ch[i].ToString(), f, b, 3 + (i * 12), 3);
}
}
//for循环用来生成一些随机的水平线
// Pen blackPen = new Pen(Color.Black, 0);
// Random rand = new Random();
// for (int i=0;i<5;i++)
// {
// int y = rand.Next(image.Height);
// g.DrawLine(blackPen,0,y,image.Width,y);
// }
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
//history back 不重复
Response.Cache.SetNoStore();//这一句
Response.ClearContent();
Response.ContentType = "image/Jpeg";
Response.BinaryWrite(ms.ToArray());
g.Dispose();
image.Dispose();
}
}