Breakpoint in Ch09Ex01

perloc · October 28th, 2010, 03:20 AM

Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Ch09Ex01
{
    public abstract class MyBase
    {
    }

    internal class MyClass : MyBase
    {
    }

    public interface IMyBaseInterface
    {
    }

    internal interface IMyBaseInterface2
    {
    }

    internal interface IMyInterface : IMyBaseInterface, IMyBaseInterface2
    {
    }

    internal sealed class MyComplexClass : MyClass, IMyInterface
    {
    }

    class Program
    {
        static void Main(string[] args)
        {
            MyComplexClass myObj = new MyComplexClass();
            Console.WriteLine(myObj.ToString());
            Console.ReadKey();
        }
    }
}

Question 1: When I put a breakpoint (to follow the sequence of the program) on "MyComplexClass myObj...." in class Program, it never jumps to one of the classes and interfaces before the class Program. Why not?
Question 2: I cannot set any breakpoint on one of the classes/interfaces before the class Program. Why not?
Question 3: I cannot put a "Console.WriteLine();" in one of the classes or interfaces. It gives an error on the "(" with the message "Invalid token '(' in class, ....." Why can I not put a Console.WriteLine() between the {} ?

Best regards,
perloc

Imar · October 28th, 2010, 05:10 AM

Hi there,

These classes and interfaces are empty and contain no runnable code yet; they are only a class or interface definition. That means you can't set breakpoints as the code will never run, and can thus never cause the debugger to break. So:

Quote:

Question 1: When I put a breakpoint (to follow the sequence of the program) on "MyComplexClass myObj...." in class Program, it never jumps to one of the classes and interfaces before the class Program. Why not?

Because they contain no executable code. Once you add a method (and call that) or a constructor, it'll be called. E.g.:

Code:

internal sealed class MyComplexClass : MyClass, IMyInterface
{
  internal MyComplexClass()
  {
  }
}

If you put a breakpoint on internal MyComplexClass(), it will break.

Quote:

Question 2: I cannot set any breakpoint on one of the classes/interfaces before the class Program. Why not?

Because they contain no executable code.

Quote:

Question 3: I cannot put a "Console.WriteLine();" in one of the classes or interfaces. It gives an error on the "(" with the message "Invalid token '(' in class, ....." Why can I not put a Console.WriteLine() between the {} ?

You can't add executable code such as Console.WriteLine in a class definition directly. You need to add it to a member such as a method, property, constructor and so on. This should work:

Code:

internal sealed class MyComplexClass : MyClass, IMyInterface
{
  internal MyComplexClass()
  {
    Console.WriteLine("Constructor called");
  }
}

Hope this helps,

Imar