Category: DotNet

Class

In C#, a class is a user-defined blueprint or prototype from which objects are created. It represents a group of related properties and methods that define the behavior of the objects.

Structure of a C# Class

A C# class typically consists of:

1. Fields: Variables that hold data.
2. Properties: Accessors for fields.
3. Methods: Functions that define behavior.
4. Constructors: Special methods for initializing objects.
5. Events: Notifications sent by an object.

Object

In C#, an object is an instance of a class. When a class is defined, no memory is allocated until an object of that class is created. An object is a real-world entity, like a car, house, or employee, that has state and behavior. The class defines the properties (state) and methods (behavior) that the objects created from the class will have.

Creating an Object

To create an object of a class, you use the new keyword followed by the class name and any required arguments for the constructor

Difference between object and class

1. Conditional Statements

if-else

• Used to execute code based on conditions.
• Provides alternative paths based on different conditions.
• Example:
• if (condition) { … } else if (anotherCondition) { … } else { … }

switch

• Provides a way to execute different actions based on the value of a variable.
• Offers a cleaner alternative to nested if-else statements for multiple conditions.
• Example:
• switch (variable) { case value1: … break; case value2: … break; default: … break; }

2. Loops

for Loop

• Iterates a statement or a block of statements repeatedly until a specified condition is met.
• Typically used when the number of iterations is known.
• Example:
• for (int i = 0; i < 5; i++) { … }

while Loop

• Repeats a statement or a block of statements while a given condition is true.
• Example:
• while (condition) { … }

do-while Loop

• Executes a block of statements repeatedly until a specified condition becomes false.
• Example:
• do { … } while (condition);

foreach Loop

• Iterates over a collection of items such as arrays or collections.
• Simplifies iteration without explicitly initializing a counter variable.
• Example:
• foreach (type variable in collection) { … }

C# Operators types

1. Arithmetic Operators

• Addition (+)
  • Adds two operands
  • Example: int sum = a + b;
• Subtraction (-)
  • Subtracts second operand from the first
  • Example: int difference = a – b;
• Multiplication (*)
  • Multiplies two operands
  • Example: int product = a * b;
• Division (/)
  • Divides numerator by denominator
  • Example: int quotient = a / b;
• Modulus (%)
  • Returns remainder of division
  • Example: int remainder = a % b;

2. Comparison Operators

Equal to (==)

• Checks if two operands are equal
• Example: bool isEqual = a == b;

Not equal to (!=)

• Checks if two operands are not equal
• Example: bool isNotEqual = a != b;

Greater than (>)

• Checks if the left operand is greater than  the right
• Example: bool isGreater = a > b;

Less than (<)

• Checks if the left operand is less than the right
• Example: bool isLess = a < b;

Greater than or equal to (>=)

• Checks if the left operand is greater than or equal to the right
• Example: bool isGreaterOrEqual = a >= b;

Less than or equal to (<=)

• Checks if the left operand is less than or equal to the right
• Example: bool isLessOrEqual = a <= b;

3. Logical Operators

Logical AND (&&)

• Returns true if both operands are true
• Example: bool result = a && b;

Logical OR (||)

• Returns true if either operand is true
• Example: bool result = a || b;

Logical NOT (!)

• Reverses the logical state of its operand
• Example: bool result = !a;

4. Assignment Operators

Assignment (=)

• Assigns right operand to left operand
• Example: a = b;

Addition assignment (+=)

• Adds right operand to left operand and assigns the result to the left operand
• Example: a += b;

Subtraction assignment (-=)

• Subtracts right operand from left operand and assigns the result to the left operand
• Example: a -= b;

Multiplication assignment (*=)

• Multiplies left operand by right operand and assigns the result to the left operand
• Example: a *= b;

Division assignment (/=)

• Divides left operand by right operand and assigns the result to the left operand
• Example: a /= b;

Modulus assignment (%=)

• Calculates modulus using two operands and assigns the result to the left operand
• Example: a %= b;

5. Increment and Decrement Operators

• Increment (++)

• Increases an integer value by one
• Example: a++;

• Decrement (–)

• Decreases an integer value by one
• Example: a–;

6. Conditional Operator (Ternary Operator)

• Conditional (?:)

• Evaluates a boolean expression and returns the result of one of two expressions
• Example: string result = (a == b) ? “Equal” : “Not Equal”;

Introduction

About C#

• C# (C-Sharp) is a programming language developed by Microsoft that runs on the .NET Framework.
• C# is used to develop web apps, desktop apps, mobile apps, games and much more.
• It is an object-oriented programming language created by Microsoft that runs on the .NET Framework.
• C# has roots from the C family, and the language is close to other popular languages like C++ and Java.
• The first version was released in year 2002. The latest version, C# 12, was released in November 2023.

C# is used for:

• Mobile applications
• Desktop applications
• Web applications
• Web services
• Web sites
• Games
• VR
• Database applications
• And much, much more!

keywords :- 

Access Modifiers

• public
• private
• protected
• internal

Data Types 

• bool
• byte
• char
• decimal
• double
• float
• int
• long
• sbyte
• short
• string
• uint
• ulong
• ushort

Control Flow

• break
• case
• catch
• continue
• default
• do
• else
• finally
• for
• foreach
• goto
• if
• lock
• return
• switch
• throw
• try
• while

Modifiers

• abstract
• async
• const
• event
• extern
• override
• partial
• readonly
• sealed
• static
• unsafe
• virtual
• volatile

Others

• as
• base
• checked
• default
• explicit
• false
• fixed
• implicit
• is
• new
• null
• operator
• sizeof
• stackalloc
• this
• true
• typeof
• unchecked
• void

Class Members

• class
• delegate
• enum
• interface
• namespace
• struct

Method Parameters

• in
• out
• ref
• params

C# Syntax :- 

using System;

namespace Example
{
    class Program
    {
        static void Main(string[] args)
        {
            // Use Console class from the System namespace
            Console.WriteLine("Hello World!");
        }
    }
}

Variable: 

variable is a storage location identified by a name that holds data which can be modified during program execution.

• int age;
• string name;

Identifier: 

an identifier is a name used to identify a variable, method, class, or any other user-defined item.

Note: 

Every C# statement ends with a semicolon ;.

Note:

C# is case-sensitive; “MyClass” and “myclass” have different meaning.

C# Output

To output values or print text in C#, you can use the WriteLine() method:

The curly braces {} marks the beginning and the end of a block of code.

C# Comments

Single-line comments start with two forward slashes (//).

Multi-line comments start with /* and ends with */.

C# Data Types

1. Value Types

2. Reference Types

3. Nullable Types

4. Enumerations (enum)

5. Structs

6. Tuples

1. Value Types

• int: 32-bit integer
• double: 64-bit floating-point
• char: 16-bit Unicode character
• bool: Boolean (true/false)
• byte: 8-bit unsigned integer
• short: 16-bit integer
• long: 64-bit integer
• float: 32-bit floating-point
• decimal: 128-bit precise decimal

Syntax Data type:-

• int number = 10;
• float price = 9.99f;
• double total = 100.50;
• char letter = ‘A’;
• string message = “Hello”;
• bool isTrue = true;+

2. Reference Types

Class Types

• Defined using class
• Example: class Person { public string Name; public int Age; }
• Array Types
• Fixed-size or dynamic collection of elements
• Example: int[] numbers = new int[5];

String Type

• Sequence of characters
• Example: string greeting = “Hello, World!”;
• Delegate Types
• Reference to methods
• Example: delegate void Del(string message);

3. Nullable Types

Allow value types to be null

Example: int? nullableInt = null;

4. Enumerations (enum)

Enums are a distinct type that consists of a set of named constants called the enumerator list.

Example:-  enum Days { Sunday, Monday, Tuesday, 

Wednesday, Thursday, Friday, Saturday }

Days today = Days.Monday;

5. Structs

Structs are value types that are typically used to encapsulate small groups of related variables.

Example: struct Point { public int X; public int Y; }

6. Tuples

Tuples are data structures that can store multiple items of different types.

Example:

var person = (Name: “John”, Age: 30);

Console.WriteLine(person.Name);  // Outputs “John”

7. Dynamic Type

The dynamic type bypasses compile-time type checking. This allows for operations that will be resolved at runtime.

dynamic myVar = 1;

myVar = “Hello”; // No compile-time error

Type Casting

Type casting in C# is the process of converting a variable from one type to another. There are two main types of casting in C#: implicit casting and explicit casting.

Implicit Casting :-

Implicit casting is automatically performed by the C# compiler when there is no risk of data loss. This usually happens when converting from a smaller type to a larger type

.

char -> int -> long -> float -> double

Explicit Casting :-

Explicit casting is required when there is a possibility of data loss or when converting from a larger type to a smaller type. This type of casting requires the use of a cast operator.

• double -> float -> long -> int -> char

Arrays

• Arrays are fixed-size collections of elements of the same type.
• Accessed using zero-based index.

Lists

• Arrays are fixed-size collections of elements of the same type.
• Accessed using zero-based index.

When to Use Each:

• Use Arrays when the size is fixed or known.
• Use Lists when flexibility and dynamic resizing are needed.

Interview Questions 

What is C#?

• C# is a modern, object-oriented programming language developed by Microsoft. It is designed for building a variety of applications that run on the .NET Framework.

What is the .NET Framework?

• The .NET Framework is a software framework developed by Microsoft that provides a controlled programming environment where software can be developed, installed, and executed on Windows-based operating systems.

Explain the public, private, protected, and internal access modifiers in C#.

• public: Accessible from any other class.
• private: Accessible only within the class in which it is declared.
• protected: Accessible within its class and by derived class instances.
• internal: Accessible only within files in the same assembly.

What is the difference between a class and an object?

• A class is a blueprint for creating objects, defining the data and behavior that the objects will have. An object is an instance of a class.

What are the pillars of Object-Oriented Programming (OOP)?

• The four pillars of OOP are Encapsulation, Inheritance, Polymorphism, and Abstraction.

About

Introduction :

.NET is a free, cross-platform, open-source developer platform for building many different types of applications. With .NET, you can use multiple languages, editors, and libraries to build for web, mobile, desktop, gaming, and IoT.

About .NET

.NET was developed by Microsoft and provides a controlled environment for software development and execution. It includes a large class library called the Framework Class Library (FCL) and provides language interoperability across several programming languages. Programs written for .NET Framework execute in a software environment known as the Common Language Runtime (CLR).

Key Components:

• .NET Framework: The original implementation for building Windows applications.
• .NET Core: A cross-platform .NET implementation for building websites, services, and console apps.
• Xamarin/Mono: For running .NET applications on Linux, macOS, and mobile devices.

System Requirements

Windows

• To install and run ASP.NET and Visual Studio 2022 Community Edition on Windows, you need to ensure your system meets the following requirements:

Operating System

• Windows 10 version 1909 or later (Home, Pro, Education, and Enterprise)
• Windows Server 2016 or later (Standard and Datacenter)
• Windows Server 2019 or later (Standard and Datacenter)

Hardware

• Processor: 1.8 GHz or faster processor; dual-core or better recommended.

RAM:

• 2 GB (4 GB recommended) [at least 2.5 GB if running on a virtual machine]
• 8 GB or more is recommended if working with Azure development.

Software

• .NET Framework 4.8 or later
• .NET 6.0 SDK (can be installed with Visual Studio)
• SQL Server (optional, if database is needed)

  For running Visual Studio 2022 and developing ASP.NET applications on macOS and Ubuntu

macOS

Operating System

macOS 10.15 (Catalina) or later

Hardware

Processor: 1.8 GHz or faster processor

RAM: 4 GB (8 GB or more recommended)

Hard Disk: Minimum 8 GB of available space

Display: Minimum resolution of 1280×800

Software

.NET 6.0 SDK

Visual Studio 2022 for Mac (Community Edition)

Ubuntu

Operating System

Ubuntu 18.04 or later

Hardware

Processor: 1.8 GHz or faster processor

RAM: 4 GB (8 GB or more recommended)

Hard Disk: Minimum 8 GB of available space

Display: Minimum resolution of 1280×720

Software

.NET 6.0 SDK

Visual Studio Code (recommended) with C# extension

.Net Frameworks editions.

Enterprise edition – It is for big organisational level projects that require licence , feature rich ide. 

Community edition –  It is for a small team of 5 people , students basically used for learning purposes. Only limited features available that are free

Professional edition – It is for business purposes , it requires a licence , and can have more features than community editions.

Visual Studio 2022 Community Installation Steps

#1

Download

• Visit the Visual Studio website.
• Choose “Visual Studio 2022 Community” and download the installer.

#2

Run Installer

• Launch the downloaded installer.
• Click “Continue” to start the installation process.

#3

Select Workloads

o Workloads -> Web & Cloud  -> ASP.NET and web development.

o Workloads -> Web & Cloud  -> Azure development.

o Workloads -> Desktop & Mobile  -> .NET Desktop development

o Workloads -> Other Toolsets  -> Data Storage and processing

Then, select the “Individual Components” tab and search for “.Net Framework project

and item templates”.

o This option will enable us to use .NET Framework 4.8 for MVC 5 style

projects.

· Select the option and then click “Install” at the bottom-right of the window.

#4

Launch Visual Studio:

• Once installed, open Visual Studio 2022.
• Sign in with a Microsoft account if prompted.

Versatility:

.NET is a versatile framework used for developing web, desktop, and mobile applications.

High Demand:

Full stack developers are in high demand, especially those proficient in .NET due to its extensive use in enterprise environments.

Comprehensive Toolset:

.NET offers a comprehensive set of tools and libraries that streamline development.

Performance:

Applications developed with .NET are known for their performance and scalability.

Cross-Platform:

With .NET Core, developers can build applications that run on Windows, macOS, and Linux.

JOB TITLES

• .NET Developer
• .Net Full Stack Developer
• Software Engineer
• Web Developer
• Senior .NET Developer
• Technical Lead
• Software Architect

.Net used by Company

01

Microsoft: As the creator of .NET, Microsoft uses it extensively for building its own products and services, including Microsoft Azure, Office 365, and many enterprise applications.

02

IBM: Uses .NET for developing enterprise applications and integrating with its other technologies.

03

Accenture: Uses .NET for developing enterprise solutions and consulting services across multiple industries.

04

Visa: Uses .NET for developing secure payment solutions and financial services applications.

05

Intel: Uses .NET for various internal applications and software development projects.

06

Capgemini: Utilizes .NET for enterprise solutions and consulting services.

07

Dell:Uses .NET for internal systems and applications, as well as for customer-facing software.

08

Siemens:Utilizes .NET for industrial automation and software solutions in various sectors, including healthcare and manufacturing.

.Net used by Freelance work/Job

YES, .NET DEVELOPMENT IS COMMONLY USED FOR FREELANCE WORK AND JOB OPPORTUNITIES ON PLATFORMS LIKE FREELANCER.COM AND UPWORK. MANY CLIENTS ON THESE PLATFORMS SEEK .NET DEVELOPERS FOR VARIOUS PROJECTS, INCLUDING WEB DEVELOPMENT, SOFTWARE DEVELOPMENT, AND MAINTENANCE TASKS.

IF YOU’RE LOOKING FOR FREELANCE .NET WORK, YOU CAN CREATE A PROFILE ON THESE PLATFORMS, SHOWCASE YOUR SKILLS, AND APPLY FOR RELEVANT JOB POSTINGS. MAKE SURE TO HIGHLIGHT YOUR EXPERIENCE WITH .NET TECHNOLOGIES, ANY RELEVANT PROJECTS YOU’VE COMPLETED, AND ANY CERTIFICATIONS YOU MAY HAVE.

Project

Stack Overflow:

• Stack Overflow: A popular community-driven question-and-answer website for programmers and developers. It’s built using ASP.NET MVC on the backend.

Visual Studio:

Microsoft’s integrated development environment (IDE) for building and debugging applications. Visual Studio itself is built using .NET.

Microsoft Azure:

Microsoft’s cloud computing platform, offering a wide range of cloud services. Many components of Azure are built using .NET technologies.

Dell’s Premier Solutions Suite: 

Dell’s software suite for managing IT infrastructure and services, built using .NET technologies.

Conclusion:

• Versatility:
• Develops web, desktop, mobile, cloud, and IoT applications using a unified framework.
• Supports multiple programming languages, including C#, F#, and VB.NET.
• Cross-Platform Development:
• .NET Core and .NET 5/6+ enable cross-platform development on Windows, macOS, and Linux.
• Offers Xamarin for mobile app development on iOS and Android.
• Comprehensive Ecosystem:
• Extensive libraries and frameworks like ASP.NET Core for web applications, Entity Framework for ORM, and Blazor for web UI development.
• Integrated tools and IDE support, notably Visual Studio.
• High Performance and Scalability:
• Efficient memory management and JIT compilation enhance performance.
• Suitable for high-traffic applications and enterprise-level solutions.
• Security:
• Built-in security features like code access security, role-based security, and cryptography libraries.
• Regular updates and patches ensure the framework stays secure.
• Integration with Microsoft Technologies:
• Seamless integration with Azure cloud services, SQL Server, Office 365, and other Microsoft products.
• Facilitates the development of end-to-end solutions within the Microsoft ecosystem.
• Strong Community and Corporate Support:
• Backed by Microsoft, ensuring long-term support and continuous improvements.
• Active developer community providing libraries, tools, and frameworks.
• Rich Development Experience:
• Powerful development tools like Visual Studio and Visual Studio Code.
• Extensive documentation, tutorials, and resources available for developers.
• Continuous Evolution:
• Regular updates and new releases introduce cutting-edge features and improvements.
• Embraces modern development practices such as microservices, DevOps, and containerization.