Question

I have a doubt in scope of varibles inside anonymous functions in C#.

Consider the program below:

 delegate void OtherDel(int x);

        public static void Main()
        {
            OtherDel del2;
            {
                int y = 4;
                del2 = delegate
                {
                      Console.WriteLine("{0}", y);//Is y out of scope
                };
            }

           del2();
        }

My VS2008 IDE gives the following errors:
[Practice is a class inside namespace Practice]

1.error CS1643: Not all code paths return a value in anonymous method of type ‘Practice.Practice.OtherDel’
2.error CS1593: Delegate ‘OtherDel’ does not take ‘0’ arguments.

It is told in a book: Illustrated C# 2008(Page 373) that the int variable y is inside the scope of del2 definition.
Then why these errors.

Answer 1

Two problem;

1. you aren’t passing anything into your del2() invoke, but it (OtherDel) takes an integer that you don’t use – you still need to supply it, though (anonymous methods silently let you not declare the params if you don’t use them – they still exist, though – your method is essentially the same as del2 = delegate(int notUsed) {...})
2. the delegate (OtherDel) must return an int – your method doesn’t

The scoping is fine.