Product Management

Overview

The Product Management module provides full Create, Read, Update, and Delete (CRUD) functionality for managing supermarket inventory. Products are linked to categories and include pricing and stock information.

Product Model

The Product model (Models/Product.cs:5-15) defines the structure for product data:

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }

    [Column(TypeName = "decimal(6,2)")]
    public decimal Price { get; set; }
    public int Stock { get; set; }
    public int CategoryId { get; set; }
    public Category? Category { get; set; }
}

Properties

Property	Type	Attributes	Description
`Id`	int	-	Unique identifier
`Name`	string	-	Product name
`Price`	decimal	`decimal(6,2)`	Product price (up to 9999.99)
`Stock`	int	-	Available quantity in inventory
`CategoryId`	int	Foreign Key	Reference to product category
`Category`	Category?	Navigation	Related category object

The Price property uses the [Column(TypeName = "decimal(6,2)")] attribute to ensure precise monetary values with 2 decimal places in the database.

CRUD Operations

List Products
Create Product
Edit Product
Delete Product

Viewing All Products

The Index page (Pages/Products/Index.cshtml.cs:22-28) retrieves and displays all products:

public async Task OnGetAsync()
{
    if (_context.Products != null)
    {
        Products = await _context.Products.ToListAsync();
    }
}

The page uses Entity Framework Core’s ToListAsync() to asynchronously fetch all products from the database.

Creating New Products

The Create page (Pages/Products/Create.cshtml.cs:26-37) adds new products to inventory:

[BindProperty]
public Product Products { get; set; } = default!;

public async Task<IActionResult> OnPostAsync()
{
    if (!ModelState.IsValid || _context.Products == null || Products == null)
    {
        return Page();
    }

    _context.Products.Add(Products);
    await _context.SaveChangesAsync();

    return RedirectToPage("./Index");
}

Validate Input

ModelState validation ensures all required fields are provided

Add to Context

Product is added to the Entity Framework context

Save Changes

Changes are persisted to the database

Redirect

User is redirected to the product list

Updating Products

The Edit page (Pages/Products/Edit.cshtml.cs:23-71) handles product updates:

public async Task<IActionResult> OnGetAsync(int? id)
{
    if (id == null || _context.Products == null)
    {
        return NotFound();
    }

    var product = await _context.Products.FirstOrDefaultAsync(m => m.Id == id);

    if (product == null)
    {
        return NotFound();
    }
    Products = product;
    return Page();
}

public async Task<IActionResult> OnPostAsync()
{
    if (!ModelState.IsValid)
    {
        return Page();
    }

    _context.Attach(Products).State = EntityState.Modified;

    try
    {
        await _context.SaveChangesAsync();
    }
    catch (DbUpdateConcurrencyException)
    {
        if (!ProductExists(Products.Id))
        {
            return NotFound();
        }
        else
        {
            throw;
        }
    }

    return RedirectToPage("./Index");
}

The edit operation includes concurrency handling to detect if the product was modified or deleted by another user during the edit process.

Deleting Products

The Delete page (Pages/Products/Delete.cshtml.cs:23-60) removes products from inventory:

public async Task<IActionResult> OnGetAsync(int? id)
{
    if (id == null || _context.Products == null)
    {
        return NotFound();
    }

    var product = await _context.Products.FirstOrDefaultAsync(m => m.Id == id);

    if (product == null)
    {
        return NotFound();
    }
    else
    {
        Products = product;
    }
    return Page();
}

public async Task<IActionResult> OnPostAsync(int? id)
{
    if (id == null || _context.Products == null)
    {
        return NotFound();
    }

    var product = await _context.Products.FindAsync(id);

    if (product != null)
    {
        Products = product;
        _context.Products.Remove(product);
        await _context.SaveChangesAsync();
    }

    return RedirectToPage("./Index");
}

The delete operation follows a two-step process:

GET: Display product details for confirmation
POST: Execute the deletion

Category Relationship

Products are linked to categories through a foreign key relationship:

public int CategoryId { get; set; }
public Category? Category { get; set; }

This allows products to be organized and filtered by category. The Category navigation property enables loading related category information when needed.

Authorization

All product management pages are protected with the [Authorize] attribute:

[Authorize]
public class IndexModel : PageModel
{
    // Implementation
}

Only authenticated users can access product management features. Unauthenticated requests are redirected to /Account/Login.

Database Context

Products are managed through the SupermarketContext (Data/SupermarketContext.cs:13):

public DbSet<Product> Products { get; set; }

Page Structure

The product management module consists of four Razor Pages:

Index

/Pages/Products/Index.cshtmlDisplays all products in a list or table format

Create

/Pages/Products/Create.cshtmlForm for adding new products

Edit

/Pages/Products/Edit.cshtmlForm for updating existing products

Delete

/Pages/Products/Delete.cshtmlConfirmation page for product deletion

Common Patterns

Model Binding

All CRUD operations use the [BindProperty] attribute for automatic form binding:

[BindProperty]
public Product Products { get; set; } = default!;

Validation

ModelState validation ensures data integrity:

if (!ModelState.IsValid)
{
    return Page();
}

Async Operations

All database operations are asynchronous for better performance:

await _context.Products.ToListAsync();
await _context.SaveChangesAsync();

Best Practices

Input Validation

Always validate user input using ModelState before saving to the database. The Product model should include appropriate data annotations for validation.

Error Handling

The edit operation includes concurrency exception handling to prevent data conflicts. Consider adding try-catch blocks for other operations as well.

Decimal Precision

The decimal(6,2) type ensures accurate price calculations without floating-point errors. Always use decimal types for monetary values.

Navigation Properties

Get Started

Core Features

Data Models

Development

Overview

Product Model

Properties

CRUD Operations

Viewing All Products

Creating New Products

Updating Products

Deleting Products

Category Relationship

Authorization

Database Context

Page Structure

Index

Create

Edit

Delete

Common Patterns

Model Binding

Validation

Async Operations

Best Practices

Build docs developers (and LLMs) love

Get Started

Core Features

Data Models

Development

​Overview

​Product Model

​Properties

​CRUD Operations

​Viewing All Products

​Creating New Products

​Updating Products

​Deleting Products

​Category Relationship

​Authorization

​Database Context

​Page Structure

Index

Create

Edit

Delete

​Common Patterns

​Model Binding

​Validation

​Async Operations

​Best Practices

Build docs developers (and LLMs) love

Overview

Product Model

Properties

CRUD Operations

Viewing All Products

Creating New Products

Updating Products

Deleting Products

Category Relationship

Authorization

Database Context

Page Structure

Common Patterns

Model Binding

Validation

Async Operations

Best Practices