C# compiler gave me the following error
CS0191: A readonly field cannot be assigned to (except in a constructor or a variable initializer)
Do I have to move the code (in my private function) into the constructor? That sounds awkward.
Note that the private method was intended only to be called by the constructor. I expect that there is some sort of attribute that I can use to mark the method corresponding.
You can literally paste "{ get; private set; }" in front of each equals sign in your readonly declarations to achieve almost the same thing (property can now be set in anywhere in class not just in constructor but at least its not changeable outside class). This is strictly true for value types but not reference types in which readonly might have an advantage.
class Foo
{
// public readonly MyInt = 30;
public int MyInt { get; private set; } = 30;
}