Question

How to write better?

public void Foo(bool isStart) {
   // Code [Common]
   if (is Start) {
      // Code [Start]
   } else {
      // Code [End]
   }
   // Code [Common]
}

or

public enum MyEnum {
   Start, End
}
public void Foo(MyEnum param) {
   // Code [Common]
   switch (param) {
      case MyEnum.Start:
         // Code [Start]
         break;
      case MyEnum.End:
         // Code [End]
         break;
   }
   // Code [Common]
}

Update: I’m looking for a small solution. “Common”, “Start” and “End” parts are very short, I do not want to split Foo into several methods.

Answer 1

How about:

public class Foo
{
    public void Start()
    {
        PreCommon();

        // Code [Start]

        PostCommon();
    }

    public void Stop()
    {
        PreCommon();

        // Code [Stop]

        PostCommon();
    }

    private void PreCommon()
    {
        // Code [Pre-Common]
    }  

    private void PostCommon()
    {
        // Code [Post-Common]
    }    
    ...

}

Methods that have a single responsibility are easier to read, easier to understand and easier to maintain.