Boxing/unboxing and Performance ?

The conversion from a value type to a reference type is known as boxing. Boxing happens automatically if a method requires an object as a parameter and a value type is passed. On the other side, a boxed value type can be converted to a value type by using unboxing. With unboxing, the cost operator is required.

var list = new ArrayList();
list.Add(44);                //boxing, convert a value type to a reference type.

int i1 = (int)list[0];        //unboxing, convert a reference type to a value type.

foreach(int i2 in list)
{
        Console.WriteLine(i2);
}

Note: Boxing and unboxing are easy to use but have a big performance impact, especially when iterating through many times.

Instead of using ArrayList, use the List class from the namespace System.Collections.Generic


var list = new List();
list.Add(44);               

int i1 = list[0];
      
foreach(int i2 in list)
{
        Console.WriteLine(i2);
}


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