📘 C# Blog Series – Blog 32 **“C# Interfaces — Multiple Behaviours को एक Structure में कैसे Define करते हैं?

📘 C# Blog Series – Blog 32

**“C# Interfaces — Multiple Behaviours को एक Structure में कैसे Define करते हैं?

(Real-Life Example: IPacketParser, IDeviceModel, IDatabaseService)”**

Inheritance आपने सीख लिया —
अब आता है Interfaces, जो OOP का सबसे flexible और powerful concept है।

Interfaces आपको allow करते हैं:

• Multiple behaviours define करना

• Clean architecture बनाना

• Loose coupling achieve करना

• DI (Dependency Injection) implement करना

• Testable code बनाना

• Multi-model GPS devices को uniformly handle करना

• Packet parser को easily switch करना

GPS servers, APIs, billing systems, microservices —
हर जगह interfaces का heavy use होता है।

---

🟦 1. Interface क्या है? (Simple Definition)

Interface =
एक contract / blueprint
जो बताता है कि class में कौन-कौन से methods होने चाहिए।

लेकिन:

❌ कोई implementation नहीं
✔ सिर्फ method definitions
✔ Class को खुद implement करना पड़ता है

Example:

interface ILogger
{
    void Log(string message);
}

---

🟢 2. Interface Implement कैसे करते हैं?

class ConsoleLogger : ILogger
{
    public void Log(string message)
    {
        Console.WriteLine(message);
    }
}

---

⭐ 3. Real-Life Example: GPS Packet Parsing Interface

हर model का packet format अलग है:

• G17

• S15

• A20

• Concox

• Coban

• Jimi

सबका parser अलग होगा—
लेकिन method name same होना चाहिए।

Define interface:

interface IPacketParser
{
    void Parse(string packet, GPSDevice device);
}

---

🌟 4. हर model अपनी parsing logic implement करेगा

G17 Parser:

class G17Parser : IPacketParser
{
    public void Parse(string packet, GPSDevice device)
    {
        Console.WriteLine("G17 Packet Parsed");
    }
}

S15 Parser:

class S15Parser : IPacketParser
{
    public void Parse(string packet, GPSDevice device)
    {
        Console.WriteLine("S15 Packet Parsed");
    }
}

अब आपका server:

IPacketParser parser = new G17Parser();
parser.Parse(pkt, device);

Parser change करना आसान।

---

⭐ 5. Real GPS Use Case: Dynamic Model Handling

Device table में:

IMEI | Model
-----|--------
8611280... | G17
8611280... | S15

Processor:

IPacketParser parser;

if (model == "G17") parser = new G17Parser();
else parser = new S15Parser();

Clean architecture with interface.

---

🟠 6. Database Service Interface (Very Useful)

You may have:

• SQL DB

• MongoDB

• FileDB

• In-memory store

Define interface:

interface IDatabaseService
{
    Task SaveLocationAsync(GPSDevice device);
}

SQL Implementation:

class SqlDbService : IDatabaseService
{
    public Task SaveLocationAsync(GPSDevice d)
    {
        // SQL Code here
    }
}

Now swapping DB is simple.

---

🔵 7. WebSocket Service Interface

interface IWebSocketService
{
    Task PushAsync(GPSDevice device);
}

Use anywhere:

_ws.PushAsync(device);

---

🟣 8. Real GPS Use Case: IDeviceModel Interface

Different device models may have:

• SOS support

• Fuel sensor

• Temperature support

• ACC

• Door sensor

Define interface:

interface IDeviceModel
{
    bool SupportsSOS { get; }
    bool SupportsFuel { get; }
    bool SupportsACC { get; }
}

Model:

class G17Model : IDeviceModel
{
    public bool SupportsSOS => true;
    public bool SupportsFuel => false;
    public bool SupportsACC => true;
}

अब features dynamic हो सकते हैं।

---

🔥 9. Interfaces + Dependency Injection = Industry Standard Architecture

Program.cs:

services.AddScoped<IPacketParser, G17Parser>();
services.AddScoped<IDatabaseService, SqlDbService>();
services.AddScoped<IWebSocketService, WsBroadcaster>();

Controller:

public DeviceController(IDatabaseService db)
{
    _db = db;
}

This is clean architecture at enterprise level.

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🧠 10. Difference: Interface vs Inheritance

Feature	Interface	Inheritance
Multiple parents allowed	✔ Yes	❌ No
Common code share	❌ No	✔ Yes
Flexibility	✔ High	Medium
Use case	Behaviors	Base class logic

GPS devices →
Inheritance + Interfaces दोनों का mix best होता है।

---

📌 11. कब Interface Use करना चाहिए?

✔ जब multiple classes same व्यवहार implement करें
✔ जब DI चाहिए
✔ जब testing आसान बनानी है
✔ जब architecture flexible चाहिए
✔ जब system large हो

---

🔚 Conclusion

C# Interfaces आपके system को बनाते हैं:

✔ Flexible
✔ Testable
✔ Loosely-coupled
✔ Architecture-friendly
✔ GPS server-ready
✔ Clean and scalable

GPS parser, database service, WebSocket server —
हर जगह interface must-have है।