You’re quite right. It turns out you can achieve the same effect using different private members, however. Thus I have updated the EvilStringHelper class to be .NET 4.0-compatible. (Why I went through the trouble of doing this, I can’t really say. Sheer curiosity, I suppose.)
the philosopher developer 
Great post! Many developers overlook the possible side effects for not using objects the way they were intended to be used.
Thank you, Daniel! Great post.
In .NET 4.0 you cannot obtain the SetChar method using reflection.
You’re quite right. It turns out you can achieve the same effect using different private members, however. Thus I have updated the EvilStringHelper class to be .NET 4.0-compatible. (Why I went through the trouble of doing this, I can’t really say. Sheer curiosity, I suppose.)
Where?
A. Batishchev: here.