关于登陆，记住我功能，以及验证码的登陆验证

1，我们在登陆中经常会遇到访问系统的某个页面无法登陆，需要走登陆页面，尽管访问的不是登陆页面，那么这是怎么做的呢？以及在登陆中有记住我以及验证码的输入功能。

今天就写了这么一个demo关于登陆验证 验证码，以及记住我功能呢

2，在这中主要用到了Session 和Cookies,Cookies 存储客户的登陆信息，Session存取验证码信息

登录页：Login.aspx

<script>
function checkcode() {
var vcode = document.getElementById("checkcode");
vcode.src = vcode.src + '1';
}
window.onload = function () {
var did = document.getElementById("width").style.width;
did = window.innerWidth - 100;
}
</script>

<form id="form1" runat="server" method="post">
用户名：<input type="text" name="username" value="<%=username %>" />
<br />
<br />
密&nbsp;码：<input type="password" name="upwd" value="<%=upwd %>" />
<br />
验证码：<input type="text" name="Vcode" />
<img src='/images/loading.gif' data-original="ValidateCode.ashx?1" id="checkcode" />
<a href="Javascript:checkcode()">看不清，换一张</a>
<br />
<br />
<div id="width">
<div >
记住我：<input type="checkbox" name="echeck" />
</div>
</div>
<br />
<input type="submit" value="登陆" />
</form>

登陆处理：Login.aspx.cs

public partial class Login : System.Web.UI.Page
{
protected string username { get; set; }
protected string upwd { get; set; }
protected void Page_Load(object sender, EventArgs e)
{
string vcode=Request["Vcode"];
//页面第一次加载，如果验证码为空，取缓存
if (string.IsNullOrEmpty(vcode))
{
HttpCookie cooike = Request.Cookies["jun"];
if (cooike!= null) {
string uinfo = Encoding.UTF8.GetString(Convert.FromBase64String(cooike.Value));
username = uinfo.Split('_')[0];
upwd = uinfo.Split('_')[1];
}
}
else {
if (vcode != null)
{
if (vcode.Equals(Session["vcode"].ToString(), StringComparison.CurrentCultureIgnoreCase))
{
//验证码正确
string sql = "select count(*) from tb_Userinfo where userName=@uname and userpwd=@upwd";
SqlParameter[] ps = new SqlParameter[] {
new SqlParameter("@uname",Request["username"]),
new SqlParameter("@upwd",Request["upwd"])
};
int count = Convert.ToInt32(SqlHelper.ExecuteScalar(sql, ps));
//用户信息正确
if (count > 0)
{
//如果勾中记住我
if (!string.IsNullOrEmpty(Request["echeck"]))
{
//登陆成功，存取Cookies信息
string uinfo = Request["username"] + "_" + Request["upwd"];
//转成64位编码
uinfo = Convert.ToBase64String(Encoding.UTF8.GetBytes(uinfo));
HttpCookie cooike = new HttpCookie("jun", uinfo)
{
Expires = DateTime.Now.AddDays(14)
};
Response.Cookies.Add(cooike);
}
Session["userinfo"] = 1;
Response.Redirect("Index.aspx");
}
else
{
Response.Write("用户名或密码错误");
}
}
else
{
Response.Write("验证码错误");
}
}
}
}
}

成功后转到Index页面  转到页面首先走Index继承的SessionStatus类  我们在这里面封装一个方法

protected void p_load(object sender, EventArgs e)
{
if (Session["userinfo"] == null)
{
Response.Redirect("Login.aspx");
}
}

在Login.aspx.cs页面先存储Session["userinfo"]=1 这样就能完成非登陆页验证是否合法登陆了

验证码我主要引用一个一般处理程序：ValidateCode.ashx

public void ProcessRequest(HttpContext context)
{
context.Response.ContentType = "image/jpeg";
CreateImage(CreateRandomCode(4)).Save(context.Response.OutputStream, ImageFormat.Jpeg);
}
//产生随机码
private string CreateRandomCode(int iLength)
{
int rand;
char code;
string randomCode = String.Empty;

//生成一定长度的验证码
System.Random random = new Random();
for (int i = 0; i < iLength; i++)
{
rand = random.Next();
if (rand%3==0)
{
code = (char)('A' + (char)(rand % 26));
}
else
{
code = (char)('0'+(char)(rand%10));
}
randomCode += code.ToString();
}

Console.WriteLine("--------------------------"+HttpContext.Current.Session.SessionID);
HttpContext.Current.Session["vcode"] = randomCode;
return randomCode;
}
//创建随机图片
private Image CreateImage(string strVerifyCode)
{
Bitmap map;
try
{
int iRandAngle = 45; //随机转动角度
int iMapWidth = (int)(strVerifyCode.Length * 21);
map = new Bitmap(iMapWidth, 28); //创建图片背景

Graphics graph = Graphics.FromImage(map);
graph.Clear(Color.AliceBlue);//清除画面，填充背景

graph.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;//模式

Random rand = new Random();

//背景噪点生成
Pen blackPen = new Pen(Color.LightGray, 0);
for (int i = 0; i < 50; i++)
{
int x = rand.Next(0, map.Width);
int y = rand.Next(0, map.Height);
graph.DrawRectangle(blackPen, x, y, 1, 1);
}

//验证码旋转，防止机器识别
char[] chars = strVerifyCode.ToCharArray();//拆散字符串成单字符数组

//文字距中
StringFormat format = new StringFormat(StringFormatFlags.NoClip);
format.Alignment = StringAlignment.Center;
format.LineAlignment = StringAlignment.Center;

//定义颜色
Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
//定义字体
string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };

for (int i = 0; i < chars.Length; i++)
{
int cindex = rand.Next(7);
int findex = rand.Next(5);

Font f = new System.Drawing.Font(font[findex], 13, System.Drawing.FontStyle.Bold);//字体样式(参数2为字体大小)
Brush b = new System.Drawing.SolidBrush(c[cindex]);

Point dot = new Point(16, 16);

float angle = rand.Next(-iRandAngle, iRandAngle);//转动的度数

graph.TranslateTransform(dot.X, dot.Y);//移动光标到指定位置
graph.RotateTransform(angle);
graph.DrawString(chars[i].ToString(), f, b, 1, 1, format);

graph.RotateTransform(-angle);//转回去
graph.TranslateTransform(2, -dot.Y);//移动光标到指定位置
}

graph.DrawRectangle(new Pen(Color.Black, 0), -chars.Length * 18, 0, map.Width - 1, map.Height - 1);//画一个边框

}
catch (ArgumentException ex)
{
map = null;
throw ex;
}
return map;
}
public bool IsReusable
{
get
{
return false;
}
}

原标题：关于登陆，记住我功能，以及验证码的登陆验证

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