NET 11 中 C# 14 新特性在云原生微服务架构的深度实践

using System;
using System.Collections.Generic;
using System.Linq;

class Order
{
    public int OrderId { get; set; }
    public decimal Amount { get; set; }
    public bool IsPaid { get; set; }
    public DateTime OrderDate { get; set; }
}

class Program
{
    static void Main()
    {
        var orders = new List<Order>
        {
            new Order { OrderId = 1, Amount = 100, IsPaid = true, OrderDate = DateTime.Now.AddDays(-5) },
            new Order { OrderId = 2, Amount = 50, IsPaid = false, OrderDate = DateTime.Now.AddDays(-3) },
            new Order { OrderId = 3, Amount = 150, IsPaid = true, OrderDate = DateTime.Now.AddDays(-7) }
        };

        var filteredOrders = orders
           .Where(o => o.Amount > 100 && o.IsPaid)
           .OrderBy(o => o.OrderDate)
           .ToList();

        foreach (var order in filteredOrders)
        {
            Console.WriteLine($"OrderId: {order.OrderId}, Amount: {order.Amount}, OrderDate: {order.OrderDate}");
        }
    }
}

- **模式匹配实战**：在一个处理不同类型消息的微服务中，使用模式匹配处理消息。

abstract class Message
{
    public string MessageId { get; set; }
}

class TextMessage : Message
{
    public string Text { get; set; }
}

class ImageMessage : Message
{
    public string ImageUrl { get; set; }
}

class Program
{
    static void Main()
    {
        Message message = new TextMessage { MessageId = "1", Text = "Hello, World!" };

        if (message is TextMessage textMsg)
        {
            Console.WriteLine($"Text Message: {textMsg.Text}");
        }
        else if (message is ImageMessage imgMsg)
        {
            Console.WriteLine($"Image Message: {imgMsg.ImageUrl}");
        }
    }
}

class SensorDataProcessor
{
    public static void ProcessSensorData()
    {
        // 使用内联数组处理小型数据集合
        Span<int> sensorReadings = stackalloc int[10];
        for (int i = 0; i < 10; i++)
        {
            sensorReadings[i] = i;
        }

        // 对传感器数据进行处理
        for (int i = 0; i < 10; i++)
        {
            sensorReadings[i] = sensorReadings[i] * 2;
        }
    }
}

- **局部函数改进应用**：在处理大型用户数据结构时，使用改进的局部函数避免数据拷贝。

class User
{
    public string Name { get; set; }
    public int Age { get; set; }
    // 其他大量属性...
}

class UserProcessor
{
    public static void ProcessUser(ref User user)
    {
        void UpdateUserAge()
        {
            user.Age++;
        }

        UpdateUserAge();
    }
}

using System.ComponentModel.DataAnnotations;

class UserRegistration
{
    [Required]
    [StringLength(50, MinimumLength = 3)]
    public string Username { get; set; }

    [Required]
    [DataType(DataType.Password)]
    [StringLength(100, MinimumLength = 6)]
    public string Password { get; set; }

    [Required]
    [EmailAddress]
    public string Email { get; set; }
}

class Program
{
    static void Main()
    {
        var registration = new UserRegistration { Username = "test", Password = "pass", Email = "invalid - email" };
        var context = new ValidationContext(registration);
        var results = new List<ValidationResult>();
        if (!Validator.TryValidateObject(registration, context, results, true))
        {
            foreach (var result in results)
            {
                Console.WriteLine(result.ErrorMessage);
            }
        }
    }
}

- **访问控制强化实践**：在一个包含敏感业务逻辑的微服务类中，设置访问权限。

public class SensitiveService
{
    // 仅内部类可访问该方法
    internal void SensitiveMethod()
    {
        // 敏感业务逻辑
    }
}