列 'username' 不属于 table Table

Question

我正在尝试使用 Visual Studio 2019 在 Asp.Net C# 中针对无效登录尝试锁定用户帐户。数据库正在使用 MySql Workbench 8.0 CE。但是面对错误

C#代码如下所示：

using System;
using System.Data;
using MySql.Data.MySqlClient;

namespace Canteen_UAT
{
    public partial class LoginDetail : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void Button1_Click1(object sender, EventArgs e)
        {
            MySqlConnection scon = new MySqlConnection("server = XXX.XXX.XX.XXX; user id = root; password = XXXXX; persistsecurityinfo = True; database = posdbms_uat");
            String myquery = "select count(*) from posdbms_uat.logindetail where username='" + TextBox1.Text + "'";
            MySqlCommand cmd = new MySqlCommand();
            cmd.CommandText = myquery;
            cmd.Connection = scon;
            MySqlDataAdapter da = new MySqlDataAdapter();
            da.SelectCommand = cmd;
            DataSet ds = new DataSet();
            da.Fill(ds);
            String uname;
            String pass;
            String status;
            //String lockstatus;
            int attemptcount = 0;

            if (ds.Tables[0].Rows.Count > 0)
            {
                uname = ds.Tables[0].Rows[0]["username"].ToString();
                pass = ds.Tables[0].Rows[0]["password"].ToString();
                status = ds.Tables[0].Rows[0]["status"].ToString();
                scon.Close();
                if (status == "Open")
                {
                    if (uname == TextBox1.Text && pass == TextBox2.Text)
                    {
                        Session["username"] = uname;
                        Response.Redirect("Order.aspx");
                    }
                    else
                    {
                        Label2.Text = "Invalid Username or Password - Relogin with Correct Username & Password. No of Attempts Remaining : " + (2 - attemptcount);
                        attemptcount = attemptcount + 1;
                    }
                }
                else if (status == "Locked")
                {
                    Label2.Text = "Your Account Locked Already : Contact Administrator";
                }
                else
                {
                    Label2.Text = "Invalid Username or Password - Relogin wit Correct Username and Password.";
                }
                if (attemptcount == 3)
                {
                    Label2.Text = "Your Account Has Been Locked Due to Three Invalid Attempts - Contact Administrator.";
                    setlockstatus(TextBox1.Text);
                    attemptcount = 0;
                }
            }
        }

        private void setlockstatus(String username1)
        {
            String mycon = "server = xxx; user id = root; password = xxx; persistsecurityinfo = True; database = posdbms_uat";                        
            String updatedata = "Update posdbms_uat.logindetail set status='Locked' where username='" + username1 + "' ";
            MySqlConnection con = new MySqlConnection(mycon);
            con.Open();
            MySqlCommand cmd = new MySqlCommand();
            cmd.CommandText = updatedata;
            cmd.Connection = con;
            cmd.ExecuteNonQuery();
        }
    }
}

不确定是什么原因造成的。

我尝试过的：

我创建了一个 table 作为 posdbms_uat，数据 table 与数据库 table 中的列名匹配并具有适当的数据类型。不确定这个错误是如何弹出的。

Answer 1

查询：

String myquery = "select count(*) from posdbms_uat.logindetail where username='" + TextBox1.Text + "'";

...只有 returns 匹配 WHERE 条件的行数 - 而不是行中的实际数据。应该通过指定您要获取的列来修复它：

String myquery = "select username, password, status from posdbms_uat.logindetail where username='" + TextBox1.Text + "'";

此外，您应该考虑使用参数化来避免 SQL 注入（参见 this SO question）。还有就是，请不要以明文形式存储密码。

列 'username' 不属于 table Table

Column 'username' does not belong to table Table

c#

mysql-workbench