### E) Event-Driven Paradigm
Flow controlled by events rather than sequential commands.

public class Button
{
    public event Action? Click;
    public void OnClick() => Click?.Invoke();
}

var button = new Button();
button.Click += () => Console.WriteLine("Button clicked!");
button.OnClick();

Used in UI, messaging systems, reactive pipelines.

---

### F) Asynchronous Paradigm
Handle I/O or long-running tasks without blocking threads.

public async Task<string> FetchAsync()
{
    using var http = new HttpClient();
    return await http.GetStringAsync("https://example.com");
}

var data = await FetchAsync();
Console.WriteLine(data);

Combines async/await with Task for clearer concurrency.

---

### G) Reactive (Optional Extension)
Treat data as streams (e.g. with IObservable): react declaratively to change over time.

---

## 4) How C# Programming Model Enables These Paradigms

| Paradigm | Model Elements (C#) |
|---------------|---------------------|
| Imperative | loops, mutable locals, branching (if, switch) |
| OOP | class, interface, abstract, virtual, override, access modifiers |
| Functional | lambdas, delegates (Func<>, Action), LINQ, record types |
| Declarative | LINQ query syntax, attributes, expression trees |
| Event-Driven | event, delegates, EventHandler, UI frameworks |
| Asynchronous | async, await, Task, CancellationToken, ValueTask |
| Reactive | observables (via libraries), continuation chains |

C# is multi-paradigm: mix domain modeling (OOP) + data transformations (functional/declarative) + async I/O + events.

---

## 5) Choosing a Paradigm (Quick Guide)

| Situation | Best Fit |
|-----------|----------|
| Rich domain entities, lifecycle | OOP |
| Data querying/filtering | Declarative (LINQ) |
| Composable transformations, testability | Functional style |
| UI interactions, user input | Event-Driven |
| Network / file / database latency | Asynchronous |
| Simple scripts / procedural tasks | Imperative |
| Live data streams / continuous updates | Reactive |

Often you combine several in one solution.

---

## 6) Summary
Paradigm = How you think and structure the solution conceptually.
Programming Model = The language/runtime mechanisms enabling those structures.
C# provides a unified model supporting multiple paradigms seamlessly.

---

## 7) Glossary (English Term + Persian Meaning)

| Term | Persian |
|------|--------|
| Programming Paradigm | پارادایم برنامه‌نویسی / سبک مفهومی |
| Programming Model | مدل برنامه‌نویسی / مکانیزم اجرایی |
| Imperative | دستوری |
| Declarative | اعلامی / деклараتی |
| Object-Oriented (OOP) | شیءگرا |
| Encapsulation | کپسوله‌سازی |
| Inheritance | ارث‌بری |
| Polymorphism | چندریختی |
| Abstraction | انتزاع |
| Class | کلاس |
| Object | شیء |
| Method | متد |
| State | حالت |
| Functional Programming | برنامه‌نویسی تابعی |
| Pure Function | تابع خالص |
| Side Effect | عارضهٔ جانبی |
| Immutability | تغییرناپذیری |
| Lambda Expression | عبارت لامبدا |
| Delegate | نماینده (تابع اشاره‌ای) |
| LINQ | چارچوب کوئری یکپارچه |
| Query Syntax | نحوهٔ نگارش کوئری |
| Expression Tree | درخت بیان |
| Event | رویداد |
| Event-Driven | رویدادمحور |
| Asynchronous / Async | ناهمگام |
| Concurrency | همزمانی |
| Task | وظیفهٔ ناهمگام |
| CancellationToken | توکن لغو |
| Record | رکورد (نوع دادهٔ مختصر) |
| Virtual | مجازی (قابل بازنویسی) |
| Override | بازنویسی |
| Abstract | انتزاعی |
| Interface | اینترفیس / قرارداد |
| Reactive | واکنشی |
| Multi-Paradigm | چندپارادایمی |
| API | رابط برنامه‌نویسی کاربردی |
| Design Pattern | الگوی طراحی |
| Refactoring | بازآرایی کد |
| Maintainability | نگهداشت‌پذیری |
| Scalability | مقیاس‌پذیری |
| Deferred Execution | اجرای مؤخر |
| DSL | زبان دامنه‌محور |
| Idempotent | ایدمپوتنت (تکرار بدون تغییر نتیجه) |

---

## 8) Tags
#programming #paradigm #programming_model #CSharp #OOP #Functional #Declarative #LINQ #Async #EventDriven #Reactive #DotNet #SoftwareDesign #CleanCode #BrainBytes #Architecture #Coding #Developer