.net - Read-Only List in C#

Question

I have some class with List-property:

class Foo {
  private List<int> myList;
}

I want provide access to this field only for read.

I.e. I want property with access to Enumerable, Count, etc. and without access to Clear, Add, Remove, etc. How I can do it?

Answer 1

You can expose a List<T> as a ReadOnlyCollection<T> by using the AsReadOnly() method

C# 6.0 and later (using Expression Bodied Properties)

class Foo { 

  private List<int> myList;

  public ReadOnlyCollection<int> ReadOnlyList => myList.AsReadOnly();

}

C# 5.0 and earlier

class Foo {

  private List<int> myList;

  public ReadOnlyCollection<int> ReadOnlyList {
     get {
         return myList.AsReadOnly();
     }
  }
}