可以运行，但是无法将注册页面的信息插入到数据库，请高手帮忙

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;public partial class register : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        this.Title = "欢迎您注册本网站";
        if (!IsPostBack)
        {
            dropPassed.Items.Add("--请选择--");
            dropPassed.Items.Add("yes");
            dropPassed.Items.Add("no");
        }
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        SqlConnection conn = new SqlConnection(@"Data Source=PC-20090321WFUM\SQLEXPRESS;Initial Catalog=Login;Integrated Security=true;");
        conn.Open();
        string check = "select * from Login where username='"+txtUsername.Text+"'";
        SqlCommand cmd = new SqlCommand(check, conn);
        SqlDataReader dr = cmd.ExecuteReader();        if (dr.Read())
        {
            Response.Write("用户已经存在！");
            dr.Close();
        }
        else
        {
            dr.Close();
            string strsql = "insert into Login(username,password,email,msn,passed,ask,answer) values('" + txtUsername.Text + "','" + txtpassword.Text + "','" + txtemail.Text + "','" +
                           txtmsn.Text + "','"+dropPassed.SelectedItem.Value+"','" + txtask.Text + "','" + txtanswer.Text + "')";
            SqlCommand com = new SqlCommand(strsql, conn);
            com.ExecuteNonQuery();
            lblmessege.Text = "注册成功,请牢记您的信息!";
        }
        conn.Close();
    }    protected void txtUsername_TextChanged(object sender, EventArgs e)
    {    }
    protected void txtpassword_TextChanged(object sender, EventArgs e)
    {    }
}