c# - 如何从查询中获取值并将其与字符串进行比较？

Question

这是我的 Society 表的架构:

Society(SocietyName, Email, Password, Status)

所以基本上我正在创建一个登录页面，用户在其中输入电子邮件和密码。如果有一封电子邮件与数据库中的电子邮件匹配，则会检查状态是否等于校长或教员或学生事务办公室。基于此，它重定向到不同的页面。以下是我的代码:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebApplication3 {
    public partial class WebForm1 : System.Web.UI.Page {
        MySql.Data.MySqlClient.MySqlConnection conn;
        MySql.Data.MySqlClient.MySqlCommand cmd;
        MySql.Data.MySqlClient.MySqlDataReader reader;
        String QueryStr;
        String name;

        protected void Page_Load(object sender, EventArgs e) { }
        protected void clicked(object sender, EventArgs e) {
            String ConnString = System.Configuration.ConfigurationManager.ConnectionStrings["Webappconstring"].ToString();
            conn = new MySql.Data.MySqlClient.MySqlConnection(ConnString);
            conn.Open();
            String QueryStr2 = "";
            QueryStr = "";
            QueryStr = "Select * from the_society_circle.society WHERE Email= '" + Emailtxt.Text + "' And Psswd=' " + passwordtxt.Text + "'";
            cmd = new MySql.Data.MySqlClient.MySqlCommand(QueryStr, conn);
            reader = cmd.ExecuteReader();

            QueryStr2 = "Select Status from the_society_circle.society where Email = '" + QueryStr + "'";
            name = "";
            while (reader.HasRows && reader.Read()) {
                name = reader["Email"].ToString();
            }


            if ((QueryStr2== "president" || QueryStr2 == "faculty member") && reader.HasRows ) {
                    Session["Email"] = name;
                    Response.BufferOutput = true;
                    Response.Redirect("WebForm2.aspx", true);
            } else {
                Emailtxt.Text = "invalid user";
            }
            conn.Close();
            }    
        }
}

问题是 if 语句永远不会执行，并且它总是打印无效的用户。

PS:我是网络开发新手:D

Answer 1

您将 QueryString2 设置为此值

QueryStr2 = "Select Status from the_society_circle.society where Email = '" + QueryStr + "'";

它永远不可能是您检查的值之一。