Resharper changing fields to readonly

Question

I am trying out Resharper and i notice that it is recommending to set instance level fields to readonly. For example:

private readonly IConnection _connection;

public RetrieveCommand(IConnection connection) {
    _connection = connection;
}

What is the benefit of marking fields like this readonly?

Answer 1

What are the benefits to marking a field as readonly in C#?

Answer 2

It recommends that you should set it to readonly because the only place you assign the _connection member is in the constructor. That is the only place you are allowed to assign to a readonly member.

See this article for an explanation: Developer Corner: Mark C# class data member as readonly when it's read only