验证码制作之一: 随机生成一个四位数字

using System;

using System.Data;

using System.Configuration;

using System.Collections;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Data.SqlClient;
public partial class UseControls_Header : System.Web.UI.UserControl

{

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

//生成一个随机数(4位数字)，在初始化时将其显示出来，作为验证码

Random yzm = new Random();

this.labVali.Text = yzm.Next(1000, 9999).ToString();

}

}

protected void btnReg_Click(object sender, EventArgs e)

{

Page.Response.Redirect("~/Module/Blog/RegPro.aspx");

}

protected void btnOK_Click(object sender, EventArgs e)

{

if (this.txtVali.Text != this.labVali.Text)

{

Response.Write("<script lanuage=javascript>alert('验证码错误');location='javascript:history.go(-1)'</script>");

}

else

{

SqlConnection con = new SqlConnection(ConfigurationManager.AppSettings["conStr"]);

con.Open();

SqlCommand com = new SqlCommand("select count(*) from tb_Blog where UserName='" + this.txtUid.Text + "' and PassWord='" + this.txtPwd.Text + "'", con);

int count = Convert.ToInt32(com.ExecuteScalar());

if (count > 0)

{

Session["UserName"] = this.txtUid.Text;

Session["PassWord"] = this.txtPwd.Text;

Page.Response.Redirect("Module/Blog/Index.aspx");

}

else

{

Response.Write("<script lanuage=javascript>alert('用户名或密码有误！');location='javascript:history.go(-1)'</script>");

return;

}

}

}

}