Program.cs

CQRS

// CQRS
// Command
// Query
// Responsibility Segregation

Command and Query

// command
public record RegisterProduct;

// query
public record GetProductDetails;

Command Handler and Query Handler

interface ICommandHandler<in TCommand>
{
    ValueTask Handle(TCommand command, CancellationToken ct);
}

interface IQueryHandler<in TQuery, TResult>
{
    ValueTask<TResult> Handle(TQuery query, CancellationToken ct);
}

Records

COMMAND

record RegisterProduct(
    Guid ProductId,
    string Sku,
    string Name,
    string? Description = null
);

Create

var registerProduct = new RegisterProduct(
    Guid.NewGuid(),
    "CC2029384",
    "Bricks"
);

Immutability

registerProduct.ProductId = Guid.NewGuid();

Nullability

<PropertyGroup>
  <Nullable>enable</Nullable> 
</PropertyGroup>

var registerProduct = new RegisterProduct(
    Guid.NewGuid(),
    "CC2029384",
    null
);

var registerProduct2 = RegisterProduct.Create(
    Guid.NewGuid(),
    "CC2029384",
    null!
);

record RegisterProduct
{
    public Guid ProductId { get; init;  }

    public string SKU { get; init;  }

    public string Name { get; init;  }

    public string? Description { get; init;  }

    public RegisterProduct(Guid productId, string sku, string name, string? description= null)
    {
        ProductId = productId;
        SKU = sku;
        Name = name;
        Description = description;
    }