What is the use of field initialisers in .NET(apart from readability)?

Question

I am just trying to learn about field initializers. I ran into the error - field initializers cannot use non static field, method or prop. While hunting an answer for this I came across THIS post.

Most up voted answer, to the post, suggests that 'this' doesn't exist until the constructor is called. Does anyone know why it is that way? Why couldn't 'this' have existed before field initializers are invoked?

In my mind, coming from a C/C++ background, 'this' is merely just a block of memory allocated on the heap. And it has to exist before any member of 'this' can be assigned a value. (So it definitely exists before field initializers).

Answer 1

When an object gets instantiated the follwing happens (simplified):

• memory is allocated
• field initializers are executed
• 'this' is created, linking all the (non-static) fields to this instance

When the field initializers are executed, the individual fields are not yet linked to the instance, so you cannot refer to another field (except the static ones) because that can only work through the reference in the 'this' instance (that does not exist yet).

To avoid confusion, you could choose not to use field initializers and initialise all the fields in the constructor body but the consequence is, you always need to explicitly declare a constructor.