为什么sql语句有记录，而sqlDataReader.read()的返回值还是false

 protected void input_sub_Click(object sender, EventArgs e)
        {
            string name = db.HtmlToTxt(input_name.Text.Trim());
            string pwd = db.HtmlToTxt(input_pwd.Text.Trim());

            string ip = System.Web.HttpContext.Current.Request.UserHostAddress;
            string md5pwd = MD5(pwd).Substring(5);

            db.open();
            string strall = "select sw_UserName,sw_state from sw_manage where sw_UserName='" + name + "' and sw_UserPassWord='" + md5pwd + "'";
            SqlDataReader sdr = db.sqlcommand(strall).ExecuteReader();
            if (sdr.Read())
            {
                int state = (int)sdr[1];
                if (state != 1)
                {
                    Response.Write("<script>alert('账户未被激活，请与管理员联系！');</script>");
                }
                else
                {
                    string aut = sdr[0].ToString();
                    HttpCookie cookie = new HttpCookie("userName", aut);
                    Response.Cookies.Add(cookie);
                    sdr.Close();
                    string str = "update sw_manage set sw_logintime=GETDATE(),sw_loginIp='" + ip + "' where sw_UserName='" + name + "' and sw_UserPassWord='" + md5pwd + "'";
                    db.checksql(str);
                    db.close();
                    Response.Redirect("main.aspx#");
                }
            }
            else
            {
                Response.Write("<script>alert('用户名或密码错误！');</script>");
                txtPwdwm.Text = "";
                sdr.Close();
                db.close();

            }
        }

sql语句查询是有记录的，

你确认strall和你在查询器中的语句完全一样吗，你最好把strall打印出来，放到查询器中试试

加个断点 调试看看先

SqlCommand cmd = new SqlCommand(strall，db)
sdr = cmd.ExecuteReader()
试试？