readonly.md

Just how read-only is "readonly" in C#?

Did you know you can modify read-only fields via reflection?

readonly2.cs

class Program
{
    public readonly int Val;

    public Program()
    {
        Val = 42;
    }

    static void Main(string[] args)
    {
        var p = new Program();
        var now = p.Val;

        // This is a compile-time error
        p.Val = 45; // try commenting out this line, see what happens...

        // But this works just fine
        p.GetType().GetField("Val").SetValue(p, 43);
        var after = p.Val;
    }
}