C#: نظرة عامة على الميزات المتقدمة

using System;
using System.Reflection;

class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
    public void SayHello() => Console.WriteLine("Hello!");
}

class Program
{
    static void Main()
    {
        Type type1 = typeof(Person);
        Type type2 = new Person().GetType();

        Console.WriteLine($"Type name: {type1.Name}");

        Console.WriteLine("Properties:");
        foreach (PropertyInfo p in type1.GetProperties())
            Console.WriteLine($"  {p.Name} ({p.PropertyType.Name})");

        Console.WriteLine("Methods:");
        foreach (MethodInfo m in type1.GetMethods(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly))
            Console.WriteLine($"  {m.Name}");
    }
}

Type name: Person
Properties:
  Name (String)
  Age (Int32)
Methods:
  get_Name
  set_Name
  get_Age
  set_Age
  SayHello

using System;
using System.Reflection;

class Dog
{
    public string Breed { get; set; } = "Unknown";
    public override string ToString() => $"Dog: {Breed}";
}

class Program
{
    static void Main()
    {
        Type type = typeof(Dog);
        object obj = Activator.CreateInstance(type)!;

        PropertyInfo prop = type.GetProperty("Breed")!;
        prop.SetValue(obj, "Husky");

        Console.WriteLine(obj);
    }
}

Dog: Husky

using System;
using System.Linq;
using System.Reflection;

class Calculator
{
    public int Add(int a, int b) => a + b;
    public double Multiply(double x, double y) => x * y;
    public void Reset() { }
}

class Program
{
    static void Main()
    {
        Calculator calc = new Calculator();
        Type type = calc.GetType();

        Console.WriteLine($"Type: {type.Name}");
        Console.WriteLine($"Namespace: {type.Namespace}");
        Console.WriteLine($"Is class: {type.IsClass}");

        Console.WriteLine("Public methods:");
        MethodInfo[] methods = type.GetMethods(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly);
        foreach (MethodInfo m in methods)
        {
            string parameters = string.Join(", ", m.GetParameters().Select(p => $"{p.ParameterType.Name} {p.Name}"));
            Console.WriteLine($"  {m.ReturnType.Name} {m.Name}({parameters})");
        }
    }
}

Type: Calculator
Namespace: 
Is class: True
Public methods:
  Int32 Add(Int32 a, Int32 b)
  Double Multiply(Double x, Double y)
  Void Reset()

using System;

class LegacyService
{
    [Obsolete("Please use NewService instead", error: false)]
    public void OldMethod() => Console.WriteLine("Old method");

    public void NewMethod() => Console.WriteLine("New method");
}

class Program
{
    static void Main()
    {
        var service = new LegacyService();
        service.OldMethod();
        service.NewMethod();
    }
}

Old method
New method

using System;

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false)]
class DescriptionAttribute : Attribute
{
    public string Text { get; }
    public DescriptionAttribute(string text) => Text = text;
}

[Description("User management service")]
class UserService
{
    [Description("Get all users")]
    public void GetAll() { }
}

class Program
{
    static void Main()
    {
        var attr = Attribute.GetCustomAttribute(typeof(UserService), typeof(DescriptionAttribute)) as DescriptionAttribute;
        Console.WriteLine(attr?.Text ?? "No description");
    }
}

User management service

using System;

interface IRepository
{
    string GetName();
}

class SqlRepository : IRepository
{
    public string GetName() => "SQL Repository";
}

class Service```<T>``` where T : class, IRepository, new()
{
    private T _repo = new T();
    public void Print() => Console.WriteLine(_repo.GetName());
}

class Program
{
    static void Main()
    {
        var service = new Service<SqlRepository>();
        service.Print();
    }
}

SQL Repository

using System;
using System.Collections.Generic;

class Program
{
    static IEnumerable```<int>``` GetNumbers()
    {
        for (int i = 0; i < 5; i++)
        {
            if (i == 3) yield break;
            yield return i;
        }
    }

    static void Main()
    {
        foreach (int n in GetNumbers())
            Console.WriteLine(n);
    }
}

0
1
2

using System;
using System.Collections.Generic;

class Program
{
    static IEnumerable```<int>``` Fibonacci(int count)
    {
        int a = 0;
        int b = 1;
        for (int i = 0; i < count; i++)
        {
            yield return a;
            int temp = a + b;
            a = b;
            b = temp;
        }
    }

    static void Main()
    {
        Console.WriteLine("Fibonacci sequence, first 10 terms:");
        foreach (int n in Fibonacci(10))
        {
            Console.Write(n + " ");
        }
        Console.WriteLine();
    }
}

Fibonacci sequence, first 10 terms:
0 1 1 2 3 5 8 13 21 34 

using System;

class Program
{
    static void Main()
    {
        int[] array = { 10, 20, 30, 40, 50 };
        Span```<int>``` span = array.AsSpan();
        Span```<int>``` slice = span.Slice(1, 3);

        slice[0] = 99;

        Console.WriteLine(string.Join(", ", array));

        Span```<int>``` stackSpan = stackalloc int[3];
        stackSpan[0] = 1;
        stackSpan[1] = 2;
        stackSpan[2] = 3;
        Console.WriteLine(string.Join(", ", stackSpan.ToArray()));
    }
}

10, 99, 30, 40, 50
1, 2, 3

using System;
using System.Text.RegularExpressions;

class Program
{
    static void Main()
    {
        string input = "Contact phone: 138-1234-5678, Email: test@example.com";

        bool hasPhone = Regex.IsMatch(input, @"\d{3}-\d{4}-\d{4}");
        Console.WriteLine($"Contains phone: {hasPhone}");

        Match phoneMatch = Regex.Match(input, @"\d{3}-\d{4}-\d{4}");
        Console.WriteLine($"Phone: {phoneMatch.Value}");

        MatchCollection emails = Regex.Matches(input, @"[\w.]+@[\w.]+");
        foreach (Match m in emails)
            Console.WriteLine($"Email: {m.Value}");

        string replaced = Regex.Replace(input, @"\d{4}", "****");
        Console.WriteLine($"Replaced: {replaced}");
    }
}

Contains phone: True
Phone: 138-1234-5678
Email: test@example.com
Replaced: Contact phone: 138-****-****, Email: test@example.com

using System;

class Program
{
    static unsafe void Main()
    {
        int value = 42;
        int* ptr = &value;

        Console.WriteLine($"Value: {*ptr}");
        Console.WriteLine($"Address: {(long)ptr}");

        int[] arr = { 1, 2, 3 };
        fixed (int* p = arr)
        {
            Console.WriteLine($"First element: {*p}");
            Console.WriteLine($"Second element: {*(p + 1)}");
        }
    }
}

Value: 42
Address: 12345678
First element: 1
Second element: 2