C# - Boxing /Unboxing and Is/AS Operator

Boxing and Unboxing in C# 

Boxing is the process of converting a value type to a reference type (object). Unboxing is the reverse process, converting a reference type back to a value type. These operations are useful when you want to work with value types in a context that requires objects.

Boxing Example:

int a = 123;
object obj = a; // Boxing: int to object

Unboxing Example:

object obj = 123;
int a = (int)obj; // Unboxing: object to int

Boxing wraps the value type inside an object, while unboxing extracts the value type from the object. Unboxing requires an explicit cast.

as Operator

The as operator is used to perform safe type conversion between compatible reference types or nullable types. If the conversion is not possible, it returns null instead of throwing an exception.

object obj = "Hello, World!";
string str = obj as string;

if (str != null)
{
    Console.WriteLine(str);
}

In this example, obj is safely cast to a string using the as operator. If obj was not a string, str would be null.

3. is Operator

The is operator checks if an object is compatible with a given type and returns a boolean value. It does not perform the actual casting but is often used in conjunction with explicit casting or the as operator.

object obj = "Hello, World!";

if (obj is string)
{
    string str = (string)obj;
    Console.WriteLine(str);
}