How to replace a class in a dll?

Question

The subject is pretty vague since I'm not sure what's the correct terminology for what I'm trying to do.

I've downloaded a dll (I don't have the source code), and using a reflection tool, I found a bug in the dll implementation. The bug is easy to fix. So let's say the bug is here:

class A  {     void f() { // BUG!!! } } 

Is there any way to implement my own A which would fix the bug and inject it in runtime to replace other A instances?

Answer 1

If you are using .NET 4.0. or higher, take a look at the: MethodRental.SwapMethodBody Method

Other way: CLR Injection: Runtime Method Replacer

Answer 2

Easiest way would be to inherit from that class and write your own implementation.

  class ParentClass             {                 public void SomeMethod() {                     //bug here                  }             }              class Child:ParentClass             {                 new public void SomeMethod() {                     // I fixed it                  }             } 

Here after, use your class.

Child child = new Child(); child.SomeMethod();