Property Initialization in C#

Properties in C# is a very convinient way to write code. A property can be initialized to a default value with the following:

public MyClass Item { get; } = new MyClass();

The Item property is initialized with a new instance of MyClass each time we access this property we will get the same instance of the class.

However when writing the following code:

public MyClass Item => new MyClass();

In that case the Item property is not initialized with any value, instead each time we access the Item property, the getter will return a new instance of MyClass. It can be easily verifiable with the following.

public object ItemA { get; } = new object();
public object ItemB => new object();

Debug.Assert(ItemA == ItemA); // true
Debug.Assert(ItemB == ItemB); // false - failure 

If we modify the object returned by an initialized property, it will modify the initialized instance of this property, and impact any other reference of it, like in the example below:

public MyClass Item { get; } = new MyClass();

var itemB = Item;

Item.member = 'test'

Console.Output(itemB.member) // 'test'

When doing this, you want to understand the lifetime of the object you are sharing and also how can other people can modify it.