Readonly field that could be assigned a value outside constructor

Question

Is there a way to have a private readonly field in a class that could be assigned a value anywhere in the class, but only once??

That is, I am looking for a private read

Answer 1

The short answer is no. The only place you can have a one-time assignment that is compiler checked is in the constructor. You could create a system where you'd get a run-time error if an assignment was attempted more than once but there is no C# construct to do this