C#

class MyClass
{
  public delegate void MyDelegate(string s)
  private object delegateObj;

  public MyClass(MyDelegate md)
  {
    this.delegateObj = md
  }

  public void DoSomething1(string s)
  {
    (this.delegateObj as MyDelegate).DynamicInvoke(new object[] { s });
  }
}

class Worker
{
  public void DoSomethingA()
  {
    MyClass.MyDelegate delegateObj = new MyClass.MyDelegate(MyFunction);
    MyClass mc = new MyClass(delegateObj)
    mc.DoSomething1("hello");
  }

  public void MyFunction(string s)
  {
    Console.WriteLine(s);
  }
}

public void DoSomething1(string s, MyDelegate md)
  {
    md(s)
  }

public void DoSomething1(string s)
  {
    (this.delegateObj as MyDelegate)(s)
  }