What is immutability and why should I worry about it?

Question

I\'ve read a couple of articles on immutability but still don\'t follow the concept very well.

I made a thread on here recently which mentioned immutability, but as

Answer 1

To put it simple: Once you create an immutable object, there's no way to change the contents of that object. Examples of .Net immutable objects are String and Uri.

When you modify a string, you simply get a new string. The original string will not change. An Uri has only readonly properties and no methods available to change the content of the Uri.

Cases that immutable objects are important are various and in most of the cases have to do with security. The Uri is a good example here. (e.g. You don't want a Uri to be changed by some untrusted code.) This means you can pass a reference to a immutable object around without having to worry the contents will ever change.

Hope this helps.