HAG_BIB_Projekt/PrototypWPFHAG/MainWindow.xaml.cs

using System.Data;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using MahApps.Metro.Controls;
using Npgsql;
using Npgsql.Replication;

namespace PrototypWPFHAG;

/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : MetroWindow
{
    public MainWindow()
    {
        InitializeComponent();
       // TestConnection();
       // Console.ReadKey();

    }

    private void loginButton_Click(object sender, RoutedEventArgs e)
    {
        // 从用户输入中获取用户名和密码
        string username = UsernameTextBox.Text;          // 获取用户名
        string password = PasswordTextBox.Password;      // 获取密码

        // 调用 ValidateUser 方法验证用户凭据
        if (ValidateUser(username, password))
        {
            MessageBox.Show("ok", "Login Successful", MessageBoxButton.OK, MessageBoxImage.Error);

        }
        else
        {
            // 如果验证失败，显示错误信息
            MessageBox.Show("Invalid username or password.", "Login Failed", MessageBoxButton.OK, MessageBoxImage.Error);
        }
    }

    private bool ValidateUser(string username, string password)
    {
        // 获取数据库连接
        using (var con = GetConnection())
        {
            con.Open(); // 打开数据库连接
            string query = "SELECT COUNT(*) FROM USER WHERE UserName = @username AND Password = @password;";

            using (var cmd = new NpgsqlCommand(query, con))
            {
                // 使用参数化查询防止 SQL 注入
                cmd.Parameters.AddWithValue("@username", username);
                cmd.Parameters.AddWithValue("@password", password);

                // 执行查询并获取结果
                int count = (int)cmd.ExecuteScalar();
                return count > 0; // 如果匹配记录数量大于 0，返回 true
            }
        }
    }

    private static void TestConnection()
    {
        using (NpgsqlConnection con = GetConnection())
        {
            con.Open();
            if (con.State == ConnectionState.Open)
            {
                Console.WriteLine("Connected to Server");
            }
        }
    }
    private static NpgsqlConnection GetConnection()
    {
        return new NpgsqlConnection(@"Server=localhost;Port=5432;User Id=postgres;Password=postgres;Database=postgres;");
    }

    //class Program
    //{
    //    static void Main(string[] args)
    //    {
    //        TestConnection();
    //        Console.ReadKey();
    //    }
    //    private static void TestConnection()
    //    {
    //        using(NpgsqlConnection con = GetConnection()){
    //            con.Open();
    //            if (con.State == ConnectionState.Open) {
    //                Console.WriteLine("Connected to Server");
    //            }
    //        }
    //    }
    //    private static NpgsqlConnection GetConnection()
    //    {
    //        return new NpgsqlConnection(@"Server=localhost;Port=5432;User Id=postgres;Password=postgres;Database=TestServer;");
    //    }
    //}
}