《－注册部分－》
错误说明：未将对象引用设置到对象的实例。我用红色注明了错误的地方。

        protected System.Web.UI.HtmlControls.HtmlInputText mail;
        protected System.Web.UI.HtmlControls.HtmlInputText pasw;
        protected System.Web.UI.HtmlControls.HtmlInputText pasw2;
        protected System.Web.UI.HtmlControls.HtmlInputText name;
        protected System.Web.UI.HtmlControls.HtmlInputText mail2;
        protected System.Web.UI.HtmlControls.HtmlInputText p1;
        protected System.Web.UI.HtmlControls.HtmlInputText p2;
                  ......

private void Submit1_ServerClick(object sender, System.EventArgs e)
        {
            
            if(checknum!=cn.Value)
            {
                Response.Write("<script>alert('对不起，你所填的认证码不正确！')</script>");
                return;
            }
            SqlConnection Con = new SqlConnection(data.constr);    
            string sql="";
            sql="select id from comp where mail='"+mail.Value+"'";
            if(hsjdata.datareader(sql))
            {
                Response.Write("<script>alert('对不起，你所填的邮件地址已经注册！')</script>");
                return;
            }
            int sv=0;
            string sex="男";
            if(c1.Checked)
                sv=1;
            if(r2.Checked)
                sex="女";
        
            [color=800000]sql="insert into comp values ('"+mail.Value+"','"+pasw.Value+"','"+name.Value+"','"+sex+"','"+p1.Value+"','"+p2.Value+"','"+p3.Value+"','"+f1.Value+"','"+f2.Value+"','"+f3.Value+"','"+mobile.Value+"','"+qq.Value+"','"+pro.Value+"','"+job.Value+"',"+sv+",'"+DateTime.Now.ToString()+"','"+post.Value+"')";[/color]                        
                          hsjdata.moddata(sql);
                          Session["mail"]=mail.Value;
                          Session["pasw"]=pasw.Value;
                          Response.Redirect("regok.aspx");            

        }