Okay, let's start by setting up the project structure, data models, and the initial Login Form. We will use Windows Forms and Entity Framework Core with SQL Server. **1. Project Setup and Dependencies:** First, create a new Windows Forms App (.NET) project named `Session1.WinForms`. Then, add the necessary NuGet packages: * `Microsoft.EntityFrameworkCore.SqlServer` * `Microsoft.EntityFrameworkCore.Design` (for migrations, if needed later) **2. Data Models and DbContext:** We'll define basic models for User, Listing, Amenity, etc., and the DbContext. using System; using System.Collections.Generic; using System.ComponentModel.DataAnnotations; namespace Session1.WinForms.Data.Models { public class User { public int Id { get; set; } [Required] [MaxLength(100)] public string Username { get; set; } [Required] public string PasswordHash { get; set; } // Store hashed passwords, not plain text [Required] [MaxLength(50)] public string FirstName { get; set; } [Required] [MaxLength(50)] public string LastName { get; set; } public DateTime BirthDate { get; set; } // Navigation property for listings owned/managed by this user public virtual ICollection ManagedListings { get; set; } = new List(); } } using System; using System.Collections.Generic; using System.ComponentModel.DataAnnotations; using System.ComponentModel.DataAnnotations.Schema; namespace Session1.WinForms.Data.Models { public class Listing { public int Id { get; set; } [Required] public int UserId { get; set; } // Foreign key to User (Owner/Manager) [Required] [MaxLength(100)] public string Title { get; set; } [Required] public int ListingTypeId { get; set; } // Foreign key to ListingType public int Capacity { get; set; } public int NumberOfRooms { get; set; } public string Address { get; set; } public string Neighborhood { get; set; } // Navigation properties [ForeignKey("UserId")] public virtual User Owner { get; set; } [ForeignKey("ListingTypeId")] public virtual ListingType ListingType { get; set; } public virtual ICollection ListingAmenities { get; set; } = new List(); public virtual ICollection AttractionDistances { get; set; } = new List(); } public class ListingType { public int Id { get; set; } [Required] [MaxLength(50)] public string Name { get; set; } } } using System.Collections.Generic; using System.ComponentModel.DataAnnotations; namespace Session1.WinForms.Data.Models { public class Amenity { public int Id { get; set; } [Required] [MaxLength(50)] public string Name { get; set; } // Navigation property for join table public virtual ICollection ListingAmenities { get; set; } = new List(); } } using System.ComponentModel.DataAnnotations.Schema; namespace Session1.WinForms.Data.Models { // Join table for Many-to-Many relationship between Listing and Amenity public class ListingAmenity { public int ListingId { get; set; } public int AmenityId { get; set; } [ForeignKey("ListingId")] public virtual Listing Listing { get; set; } [ForeignKey("AmenityId")] public virtual Amenity Amenity { get; set; } } } using System.Collections.Generic; using System.ComponentModel.DataAnnotations; namespace Session1.WinForms.Data.Models { public class Attraction { public int Id { get; set; } [Required] [MaxLength(100)] public string Name { get; set; } // Navigation property for join table public virtual ICollection AttractionDistances { get; set; } = new List(); } } using System.ComponentModel.DataAnnotations.Schema; namespace Session1.WinForms.Data.Models { // Stores distance/time from a Listing to an Attraction public class AttractionDistance { public int Id { get; set; } public int ListingId { get; set; } public int AttractionId { get; set; } public decimal DistanceKm { get; set; } public int TimeMinutes { get; set; } // Assuming driving/walking time [ForeignKey("ListingId")] public virtual Listing Listing { get; set; } [ForeignKey("AttractionId")] public virtual Attraction Attraction { get; set; } } } using Microsoft.EntityFrameworkCore; using Session1.WinForms.Data.Models; namespace Session1.WinForms.Data { public class AppDbContext : DbContext { // Define DbSet properties for each entity (table) public DbSet Users { get; set; } public DbSet Listings { get; set; } public DbSet ListingTypes { get; set; } public DbSet Amenities { get; set; } public DbSet ListingAmenities { get; set; } public DbSet Attractions { get; set; } public DbSet AttractionDistances { get; set; } // Replace with your actual connection string // Consider using configuration (appsettings.json) for production private const string ConnectionString = "Server=(localdb)\\mssqllocaldb;Database=Session1;Trusted_Connection=True;MultipleActiveResultSets=true"; protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) { if (!optionsBuilder.IsConfigured) { optionsBuilder.UseSqlServer(ConnectionString); } } protected override void OnModelCreating(ModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); // Configure composite primary key for the join table modelBuilder.Entity() .HasKey(la => new { la.ListingId, la.AmenityId }); // Configure relationships (optional if conventions are followed) modelBuilder.Entity() .HasOne(la => la.Listing) .WithMany(l => l.ListingAmenities) .HasForeignKey(la => la.ListingId); modelBuilder.Entity() .HasOne(la => la.Amenity) .WithMany(a => a.ListingAmenities) .HasForeignKey(la => la.AmenityId); // Seed initial data if necessary (example) // modelBuilder.Entity().HasData( // new ListingType { Id = 1, Name = "Apartment" }, // new ListingType { Id = 2, Name = "House" }, // new ListingType { Id = 3, Name = "Hotel Room" } // ); } } } using System; using System.Security.Cryptography; using System.Text; namespace Session1.WinForms.Services { ///

/// Simple helper for hashing and verifying passwords. /// NOTE: For production, use a stronger hashing library like BCrypt.Net. ///

public static class PasswordHelper { public static string HashPassword(string password) { if (string.IsNullOrEmpty(password)) { throw new ArgumentNullException(nameof(password)); } using (var sha256 = SHA256.Create()) { byte[] hashedBytes = sha256.ComputeHash(Encoding.UTF8.GetBytes(password)); // Convert byte array to a string representation (e.g., Base64 or Hex) return Convert.ToBase64String(hashedBytes); } } public static bool VerifyPassword(string password, string hashedPassword) { if (string.IsNullOrEmpty(password) || string.IsNullOrEmpty(hashedPassword)) { return false; } string hashOfInput = HashPassword(password); return StringComparer.OrdinalIgnoreCase.Compare(hashOfInput, hashedPassword) == 0; } } } using Session1.WinForms.Data; using Session1.WinForms.Data.Models; using System.Linq; using System.Threading.Tasks; namespace Session1.WinForms.Services { public class AuthService { private readonly AppDbContext _context; public AuthService(AppDbContext context) { _context = context; } ///

/// Attempts to authenticate a user. ///

/// Username /// Plain text password /// The authenticated User object or null if authentication fails. public async Task AuthenticateUserAsync(string username, string password) { if (string.IsNullOrWhiteSpace(username) || string.IsNullOrWhiteSpace(password)) { return null; // Invalid input } // Find user by username (case-insensitive comparison might be needed depending on requirements) var user = await _context.Users.FirstOrDefaultAsync(u => u.Username == username); if (user == null) { return null; // User not found } // Verify the password if (PasswordHelper.VerifyPassword(password, user.PasswordHash)) { return user; // Authentication successful } return null; // Incorrect password } // Placeholder for employee login if needed later public async Task AuthenticateEmployeeAsync(string employeeId, string password) { // Implement employee authentication logic here if required await Task.Delay(100); // Simulate async work return false; // Placeholder } } } using Session1.WinForms.Data; using Session1.WinForms.Services; using System; using System.Windows.Forms; namespace Session1.WinForms.Forms { public partial class LoginForm : Form { private readonly AuthService _authService; public LoginForm() { InitializeComponent(); // Ideally, use Dependency Injection, but for simplicity, create context directly var dbContext = new AppDbContext(); _authService = new AuthService(dbContext); // Set initial state passwordTextBox.UseSystemPasswordChar = true; } private void showPasswordCheckBox_CheckedChanged(object sender, EventArgs e) { // Toggle password visibility passwordTextBox.UseSystemPasswordChar = !showPasswordCheckBox.Checked; } private async void loginButton_Click(object sender, EventArgs e) { string username = usernameTextBox.Text; string password = passwordTextBox.Text; // string employeeId = employeeTextBox.Text; // If employee login is used if (string.IsNullOrWhiteSpace(username) || string.IsNullOrWhiteSpace(password)) { MessageBox.Show("Please enter both username and password.", "Login Error", MessageBoxButtons.OK, MessageBoxIcon.Warning); return; } // Disable controls during login attempt SetControlsEnabled(false); loginButton.Text = "Logging in..."; // Provide visual feedback try { var user = await _authService.AuthenticateUserAsync(username, password); if (user != null) { // Login successful MessageBox.Show($"Welcome, {user.FirstName}!", "Login Successful", MessageBoxButtons.OK, MessageBoxIcon.Information); // TODO: Handle "Stay Logged In" checkbox state if needed (e.g., save token) // Open the Management Form and hide/close the Login Form // Pass the authenticated user if needed var managementForm = new ManagementForm(user); managementForm.FormClosed += (s, args) => this.Close(); // Close login form when management form closes managementForm.Show(); this.Hide(); } else { // Login failed MessageBox.Show("Invalid username or password.", "Login Failed", MessageBoxButtons.OK, MessageBoxIcon.Error); } } catch (Exception ex) { // Log the exception details (ex) MessageBox.Show($"An error occurred during login: {ex.Message}", "Login Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } finally { // Re-enable controls SetControlsEnabled(true); loginButton.Text = "Login"; } } private void createAccountButton_Click(object sender, EventArgs e) { // Open the Registration Form modally using (var registrationForm = new RegistrationForm()) { this.Hide(); // Hide login form while registration is open registrationForm.ShowDialog(this); // Show registration form modally this.Show(); // Show login form again when registration closes } } private void cancelButton_Click(object sender, EventArgs e) { this.Close(); // Close the application or return to previous state } private void SetControlsEnabled(bool enabled) { usernameTextBox.Enabled = enabled; passwordTextBox.Enabled = enabled; // employeeTextBox.Enabled = enabled; // If used showPasswordCheckBox.Enabled = enabled; stayLoggedInCheckBox.Enabled = enabled; loginButton.Enabled = enabled; createAccountButton.Enabled = enabled; cancelButton.Enabled = enabled; } // Required method for Designer support - do not modify // the contents of this method with the code editor. private void InitializeComponent() { this.usernameLabel = new System.Windows.Forms.Label(); this.passwordLabel = new System.Windows.Forms.Label(); this.usernameTextBox = new System.Windows.Forms.TextBox(); this.passwordTextBox = new System.Windows.Forms.TextBox(); this.loginButton = new System.Windows.Forms.Button(); this.cancelButton = new System.Windows.Forms.Button(); this.showPasswordCheckBox = new System.Windows.Forms.CheckBox(); this.stayLoggedInCheckBox = new System.Windows.Forms.CheckBox(); this.createAccountButton = new System.Windows.Forms.Button(); this.employeeLabel = new System.Windows.Forms.Label(); this.employeeTextBox = new System.Windows.Forms.TextBox(); this.SuspendLayout(); // // usernameLabel // this.usernameLabel.AutoSize = true; this.usernameLabel.Location = new System.Drawing.Point(40, 70); this.usernameLabel.Name = "usernameLabel"; this.usernameLabel.Size = new System.Drawing.Size(78, 20); this.usernameLabel.TabIndex = 0; this.usernameLabel.Text = "Username:"; // // passwordLabel // this.passwordLabel.AutoSize = true; this.passwordLabel.Location = new System.Drawing.Point(40, 110); this.passwordLabel.Name = "passwordLabel"; this.passwordLabel.Size = new System.Drawing.Size(73, 20); this.passwordLabel.TabIndex = 2; this.passwordLabel.Text = "Password:"; // // usernameTextBox // this.usernameTextBox.Location = new System.Drawing.Point(130, 67); this.usernameTextBox.Name = "usernameTextBox"; this.usernameTextBox.Size = new System.Drawing.Size(250, 27); this.usernameTextBox.TabIndex = 1; // // passwordTextBox // this.passwordTextBox.Location = new System.Drawing.Point(130, 107); this.passwordTextBox.Name = "passwordTextBox"; this.passwordTextBox.Size = new System.Drawing.Size(250, 27); this.passwordTextBox.TabIndex = 3; // // loginButton // this.loginButton.Location = new System.Drawing.Point(130, 200); this.loginButton.Name = "loginButton"; this.loginButton.Size = new System.Drawing.Size(120, 35); this.loginButton.TabIndex = 7; this.loginButton.Text = "Login"; this.loginButton.UseVisualStyleBackColor = true; this.loginButton.Click += new System.EventHandler(this.loginButton_Click); // // cancelButton // this.cancelButton.BackColor = System.Drawing.Color.Red; this.cancelButton.ForeColor = System.Drawing.SystemColors.ControlLightLight; this.cancelButton.Location = new System.Drawing.Point(260, 200); this.cancelButton.Name = "cancelButton"; this.cancelButton.Size = new System.Drawing.Size(120, 35); this.cancelButton.TabIndex = 8; this.cancelButton.Text = "Cancel"; this.cancelButton.UseVisualStyleBackColor = false; this.cancelButton.Click += new System.EventHandler(this.cancelButton_Click); // // showPasswordCheckBox // this.showPasswordCheckBox.AutoSize = true; this.showPasswordCheckBox.Location = new System.Drawing.Point(130, 140); this.showPasswordCheckBox.Name = "showPasswordCheckBox"; this.showPasswordCheckBox.Size = new System.Drawing.Size(132, 24); this.showPasswordCheckBox.TabIndex = 4; this.showPasswordCheckBox.Text = "Show Password"; this.showPasswordCheckBox.UseVisualStyleBackColor = true; this.showPasswordCheckBox.CheckedChanged += new System.EventHandler(this.showPasswordCheckBox_CheckedChanged); // // stayLoggedInCheckBox // this.stayLoggedInCheckBox.AutoSize = true; this.stayLoggedInCheckBox.Location = new System.Drawing.Point(130, 170); this.stayLoggedInCheckBox.Name = "stayLoggedInCheckBox"; this.stayLoggedInCheckBox.Size = new System.Drawing.Size(127, 24); this.stayLoggedInCheckBox.TabIndex = 5; this.stayLoggedInCheckBox.Text = "Stay Logged In"; this.stayLoggedInCheckBox.UseVisualStyleBackColor = true; // // createAccountButton // this.createAccountButton.Location = new System.Drawing.Point(130, 245); this.createAccountButton.Name = "createAccountButton"; this.createAccountButton.Size = new System.Drawing.Size(250, 35); this.createAccountButton.TabIndex = 9; this.createAccountButton.Text = "Create Account"; this.createAccountButton.UseVisualStyleBackColor = true; this.createAccountButton.Click += new System.EventHandler(this.createAccountButton_Click); // // employeeLabel // this.employeeLabel.AutoSize = true; this.employeeLabel.Location = new System.Drawing.Point(40, 30); this.employeeLabel.Name = "employeeLabel"; this.employeeLabel.Size = new System.Drawing.Size(78, 20); this.employeeLabel.TabIndex = 10; this.employeeLabel.Text = "Employee ID (Optional):"; // // employeeTextBox // this.employeeTextBox.Location = new System.Drawing.Point(200, 27); this.employeeTextBox.Name = "employeeTextBox"; this.employeeTextBox.Size = new System.Drawing.Size(180, 27); this.employeeTextBox.TabIndex = 0; // Make it first in tab order // // LoginForm // this.AcceptButton = this.loginButton; // Press Enter to Login this.AutoScaleDimensions = new System.Drawing.SizeF(8F, 20F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.CancelButton = this.cancelButton; // Press Esc to Cancel this.ClientSize = new System.Drawing.Size(422, 303); this.Controls.Add(this.employeeTextBox); this.Controls.Add(this.employeeLabel); this.Controls.Add(this.createAccountButton); this.Controls.Add(this.stayLoggedInCheckBox); this.Controls.Add(this.showPasswordCheckBox); this.Controls.Add(this.cancelButton); this.Controls.Add(this.loginButton); this.Controls.Add(this.passwordTextBox); this.Controls.Add(this.usernameTextBox); this.Controls.Add(this.passwordLabel); this.Controls.Add(this.usernameLabel); this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog; this.MaximizeBox = false; this.MinimizeBox = false; this.Name = "LoginForm"; this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen; this.Text = "Login"; this.ResumeLayout(false); this.PerformLayout(); } #endregion private System.Windows.Forms.Label usernameLabel; private System.Windows.Forms.Label passwordLabel; private System.Windows.Forms.TextBox usernameTextBox; private System.Windows.Forms.TextBox passwordTextBox; private System.Windows.Forms.Button loginButton; private System.Windows.Forms.Button cancelButton; private System.Windows.Forms.CheckBox showPasswordCheckBox; private System.Windows.Forms.CheckBox stayLoggedInCheckBox; private System.Windows.Forms.Button createAccountButton; private System.Windows.Forms.Label employeeLabel; private System.Windows.Forms.TextBox employeeTextBox; // --- Placeholder Forms --- // These need to be fully implemented later public class RegistrationForm : Form { public RegistrationForm() { this.Text = "Register - Placeholder"; this.Size = new System.Drawing.Size(400, 500); this.StartPosition = FormStartPosition.CenterParent;} } public class ManagementForm : Form { public ManagementForm(User user) { this.Text = $"Management ({user.Username}) - Placeholder"; this.Size = new System.Drawing.Size(800, 600); this.StartPosition = FormStartPosition.CenterScreen;} } } } using Session1.WinForms.Forms; using System; using System.Windows.Forms; namespace Session1.WinForms { internal static class Program { ///

/// The main entry point for the application. ///

[STAThread] static void Main() { // To customize application configuration such as set high DPI settings or default font, // see https://aka.ms/applicationconfiguration. ApplicationConfiguration.Initialize(); Application.Run(new LoginForm()); // Start with the Login Form } } } **Explanation:** 1. **Models:** Defined basic C# classes (`User`, `Listing`, `Amenity`, etc.) that represent the database tables. Added `[Required]`, `[MaxLength]`, and `[ForeignKey]` attributes for basic validation and relationships. 2. **AppDbContext:** Created the Entity Framework Core `DbContext` (`AppDbContext`). It includes `DbSet` properties for each model and configures the database connection string (hardcoded for now) and model relationships (like the many-to-many `ListingAmenity`). 3. **PasswordHelper:** Added a static class for basic password hashing (using SHA256). **Note:** For production, use a more robust library like BCrypt.Net. 4. **AuthService:** Created a service class to handle user authentication logic, interacting with the `AppDbContext`. 5. **LoginForm.cs:** * Created the main `LoginForm` class. * Added UI controls (Labels, TextBoxes, CheckBoxes, Buttons) using the designer-generated `InitializeComponent` method (included in the code). * Implemented event handlers: * `showPasswordCheckBox_CheckedChanged`: Toggles password visibility. * `loginButton_Click`: Calls `AuthService` to authenticate, handles success (opens `ManagementForm` placeholder) or failure (shows message box), and manages UI state during login. Uses `async/await` for non-blocking UI. * `createAccountButton_Click`: Opens the `RegistrationForm` placeholder modally. * `cancelButton_Click`: Closes the form. * Set `StartPosition` to `CenterScreen`. * Set `CancelButton` color to Red. * Added placeholder classes for `RegistrationForm` and `ManagementForm` so the code compiles. 6. **Program.cs:** Modified the entry point to start the application with `LoginForm`. **Next Steps:** 1. Implement the `RegistrationForm` with its fields, validation, and user creation logic. 2. Implement the `ManagementForm` with its tabs and basic functionality. 3. Implement the `ListingForm` for adding/editing listings. 4. Write the unit test for user registration. 5. Refine error handling, UI details, and potentially replace direct `DbContext` instantiation with Dependency Injection. 6. Ensure the database "Session1" is created and the schema matches the models (you might need to use EF Core Migrations: `Add-Migration InitialCreate` and `Update-Database` in the Package Manager Console).