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我目前正在尝试用 C# 设计一台 atm 机器，对此我很陌生。我希望我的登录屏幕在 3 次尝试登录失败后返回到我的欢迎屏幕，但我不知道从哪里开始以及如何在我的程序中实现我的代码来执行此操作。

我当前的登录屏幕代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;
using System.Data.Common;

namespace bankkk
{
    public partial class FrmLogin : Form
    {
        public FrmLogin()
        {
            InitializeComponent();
        }

        public static OleDbConnection con = new OleDbConnection();

        string dbProvider;
        string dbSource;

        OleDbDataAdapter da;

        public static DataSet ds1 = new DataSet();

        string sql;
        string pin;
        int rownum = 0;
        bool valid = false;

        private void FrmLogin_Load(object sender, EventArgs e)
        {
            dbProvider = "PROVIDER=Microsoft.ACE.OLEDB.12.0;";
            dbSource = "Data Source = 'd:\\bank11.accdb'";
            con.ConnectionString = dbProvider + dbSource;
            ds1 = new DataSet();
            con.Open();
            sql = " SELECT tblCustomers.* FROM tblCustomers";
            da = new OleDbDataAdapter(sql, con);
            rownum = da.Fill(ds1, "tblCustomers");

            con.Close();
        }

        private void btnexit_Click(object sender, EventArgs e)
        {

            System.Environment.Exit(0);
            this.Close();

        }


        //METHOD VALIDATE

        private bool validate()
        {
            ds1 = new DataSet();
            con.Open();

            sql = "SELECT tblCustomers.* FROM tblCustomers WHERE ((tblCustomers.AccountNo) = '" + txtAccount.Text + "')";
            da = new OleDbDataAdapter(sql, con);
            rownum = da.Fill(ds1, "tblCustomers");
            con.Close();

            if (rownum != 1)
            {
                MessageBox.Show("Not a valid Account");
                return false;
            }
            else
            {
                pin = ds1.Tables["tblCustomers"].Rows[0][4].ToString();
                if (pin == txtPin.Text)
                {
                    return true;
                }
                else
                {
                    MessageBox.Show("INVALID PIN");
                    return false;
                }
            }
        }

        private void btnLogin_Click(object sender, EventArgs e)
        {
            valid = validate();
            if (valid == true)
            {
                if (txtAccount.Text == "11111111" && txtPin.Text == "9999")
                {
                    Frmmanager Manager = new Frmmanager();
                    this.Close();
                    Manager.Show();
                }
                else
                {
                    frmaccount account = new frmaccount();
                    this.Close();
                    account.Show();

                    {
                        txtAccount.Clear();
                        txtPin.Clear();
                    }
                }
            }
        }

        private void btnlogin_Click_1(object sender, EventArgs e)
        {
            valid = validate();
            if (valid == true)
            {
                if (txtAccount.Text == "11111111" && txtPin.Text == "9999")
                {
                    Frmmanager Manager = new Frmmanager();
                    this.Close();
                    Manager.Show();
                }
                else
                {
                    frmaccount account = new frmaccount();
                    this.Close();
                    account.Show();

                    {
                        txtAccount.Clear();
                        txtPin.Clear();
                    }
                }
            }
        }
    }
}
4

2 回答 2

1

你说返回到我的欢迎屏幕，所以我假设你显示的是FrmLoginusing.ShowDialog()而不是.Show(). 这样，您只需要关闭旧表单。

如果你只是在做.Show()，你可以这样做：

public partial class FrmWelcome {

    //in some part of your code...
    var frmLogin = new FrmLogin();

    //when the login form is closed, show this one.
    //Depending on your application, you might want to add some boolean variable
    //to the Login Form that will be true if the user authentication failed, and 
    //show this form again only if it is true.
    frmLogin.Closed += (s, e) => this.Show();

    this.Hide();
    frmLogin.Show();
}

试试下面的代码。这个想法是有一个failedAttempts变量，每次验证代码失败时都会递增。当它等于 3 时，您只需关闭表单（见上文）。

namespace bankkk
{
    public partial class FrmLogin : Form
    {
        public FrmLogin()
        {
            InitializeComponent();
        }

        ...

        int failedAttempts = 0;

        private void btnlogin_Click_1(object sender, EventArgs e)
        {
            valid = validate();
            if (!valid) {
                //Increment the number of failed attempts
                failedAttempts += 1;

                //If equal to 3
                if (failedAttempts == 3) {
                    //Just close this window
                    this.Close();
                }
            }
            else
            {
                //the same code you were using...
            }
        }
    }
}
于 2013-03-08T20:08:11.477 回答
0

您可以在程序中添加一个变量并增加它以限制尝试登录的次数。要限制帐户的尝试次数，请添加一个表以将登录信息（包括无效尝试）存储到您的数据库中。将该表链接到您的客户表。当无效尝试登录到有效客户帐户时，增加无效尝试次数并将其写回登录表。成功登录后，您可以将无效尝试次数设置为 0。

于 2013-03-08T20:10:58.857 回答