留言板----一个登陆页面（带验证码）
<body>
<form id="form1" runat="server">
<div>
<center>
<table border="1" cellpadding="0" cellspacing="0">
<tr>
<td colspan="2" style="color: #ffffff; background-color: #669900; height: 32px">
<span style="font-size: 24pt">
登陆
</span>
</td>
</tr>
<tr>
<td>用 户 名： </td>
<td>
<asp:TextBox ID="unameTextBox" runat="server"></asp:TextBox>
</td>
</tr>
<tr>
<td>
密        码：
</td>
<td>
<asp:TextBox ID="PasswordTextBox" runat="server" TextMode="Password"></asp:TextBox>
</td>
</tr>
<tr>
<td>
图片验证：
</td>
<td align="left">
<asp:TextBox ID="ValidateTextBox" runat="server" Width="71px" Height="25px"></asp:TextBox>
<asp:ImageButton ID="ValidateImageButton" runat="server" />
</td>
</tr>
<tr>
<td colspan="2">
<asp:Label ID="MsgLabel" runat="server" ForeColor="red" Font-Size="small"></asp:Label>
</td>
</tr>
<tr>
<td colspan="2">
<asp:Button ID="LandButton" runat="server" Text="登陆" OnClick="LandButton_Click" />
</td>
</tr>
</table>
</center>
</div>
</form>
</body>
后台代码：
public partial class login : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
this.ValidateImageButton.ImageUrl = "image.aspx";
}
protected void LandButton_Click(object sender, EventArgs e)
{
if ((this.unameTextBox.Text == "") || (this.PasswordTextBox.Text==""))
{
MsgLabel.Text = "用户名与密码不能为空！";
}
else
{
SqlConnection con = db.CreateConnection();
con.Open();
string strsql = "select upass from login where uname='"+this.unameTextBox.Text+"'";
SqlCommand cmd = new SqlCommand(strsql, con);
DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter(strsql, con);
da.Fill(ds, "mytable");
try
{
if (this.PasswordTextBox.Text == ds.Tables[0].Rows[0].ItemArray[0].ToString().Trim())
{
string curuser = this.unameTextBox.Text;
Session["uname"] = this.unameTextBox.Text.Trim();
string aa = this.ValidateTextBox.Text.ToString();
if (aa == Convert.ToString(Session["Image"])||aa==Convert.ToString(Session["Image"]).ToLower())
{
Response.Redirect("message.aspx");
}
else
{
Response.Write("<script>alert('验证码错误，请重新输入！')</script>");
}
}
else
{
MsgLabel.Text = "用户名或者密码错误！";
}
}
catch
{
MsgLabel.Text = "sorry!你输入的用户名不存在！";
}
con.Close();
}
}
}
首先创建一个新的页面image.aspx，此页面只需要编写后台代码即可，代码如下：
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Drawing;
public partial class image : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//产生验证图片
this.GenImg(this.GenCode(4));
//将验证码存储到Session中，以便需要时进行验证
Session["image"] = this.GenCode(4);
}
//任意产生4个验证码
private string GenCode(int p_num)
{
string[] source ={ "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G",
"G", "H", "I", "G", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"};
string code = "";
Random rd = new Random();
for (int i = 0; i < p_num; i++)
{
code += source[rd.Next(0, source.Length)];
}
return code;
}
//生产图片
private void GenImg(string p_code)
{
//定义一个画板
Bitmap myPalette = new Bitmap(60,20);
//在画板上定义绘图的实例
Graphics gh = Graphics.FromImage(myPalette);
//定义一个矩形
Rectangle rc = new Rectangle(0,0,60,20);
//填充矩形
gh.FillRectangle(new SolidBrush(Color.Blue), rc);
//在矩形内画出字符串
gh.DrawString(p_code, new Font("宋体", 16), new SolidBrush(Color.White), rc);
//将图片显示出来
myPalette.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
gh.Dispose();
myPalette.Dispose();
}
}
