C# Fundamentals - Part 1

An Introduction to C#

Demo of C# program

Type example

All the value types are immutable

Classes and Objects

All the classes in .NET derives from System.Object

Demo with Circle and Square

Internal is default accessibility of class in c#
Private is default accessibility of member of class in c#

Demo of Abstract class

Here abstract keyword is used to prevent create objects for base class with new keyword

Virtual method dispatched based on type of the object

Regular method dispatched based on type of the variable

Method hiding:

we could achieve method hiding by adding virtual keyword at base class method and not adding override keyword at derived class.

Change the behavior:

to Change the behavior of base class method, we need to add virtual method at base class and override method at derived class

C# - Types

Demo of Methods parameters

IS Keyword:

Checks if an object is compatible with a given type. For example, the following code can determine if an object is an instance of the MyObject type, or a type that derives from MyObject.
        Class1 a;
        Class2 b;

        if (o is Class1)
        {
            Console.WriteLine("o is Class1");
            a = (Class1)o;
            // Do something with "a."
        }

Equal Method:

Determines whether the specified object is equal to the current object.

If the current instance is a reference type, the Equals(Object) method tests for reference equality, and a call to the Equals(Object) method is equivalent to a call to the ReferenceEquals method. Reference equality means that the object variables that are compared refer to the same object.

If the current instance is a value type, the Equals(Object) method tests for value equality.

Demo of Array

C# - Events, Properties, and Methods

Demo of Method:

Auto property:

Demo of Private Delegates:

Demo of Public Delegates:

Demo of Event Subscriber Delegates

Demo of constructor

C# - Flow Control and Exceptions

"Throw" will rethrow the exception with entire stack information.

"Throw ex" will rethrow the exception with stack information from current throw statement