class in a class?

[JustSomeGuy]

namespace ScratchDetection
{
    class ImageProcessing
    {
         public class hough
         {
         }
    }
}

Can I have a class within a class?
If so how do I access the methods?

[darwen]

Can I have a class within a class?

Oh yes. And a class in a class can access the 'parent' classes private members making it rather useful.

If so how do I access the methods?

Like this :

public class Outer
{
    private int _value;

    public Outer(int value)
    {
        _value = value;
    }

    public class Inner
    {
        public int GetOuterValue(Outer value)
        {
            // gain access to the parent classes private member variable
            return value._value;
        }        
    }
}

// example code
Outer.Inner inner = new Outer.Inner();
Outer outer = new Outer(100);
int outerValue = inner.GetOuterValue(outer);

Get it ?

Darwen.

[opedog]

@zdavis - I don't see any nested classes in your example. Maybe a misplaced bracket?

@JustSomeGuy - What I'd suggest here is to just try it out. Nested classes in C# are very useful for limiting the scope of classes and avoiding unnecessary namespace clutter.

[zdavis]

opedog....thank you for notice. I should pay a little more attention next time with my brackets.

@justsomeguy - sorry if I confused with my misleading example.

[JustSomeGuy]

Thanks all.. Never a problem.

A question about instantiation...
If The outer class is instantiated by the user...
When does the inner class get instantiated?

[boudino]

When does the inner class get instantiated?

If you call a constructor of it with the new keyword. Don't miss it with Java, there is a difference. Inner classes in C# is primary a matter of scope. They have access to private members of outer class and are accessible only via their outer class, so they share their accessibility.

[opedog]

Yup, nested classes are instantiated the exact same way as all the others. For instance:

public class Class1
{
  public class NestedClass1
  {
  }
}

You can instantiated NestedClass1 this way:

Class1.NestedClass1 c = new Class1.NestedClass1()

Or, if you're inside Class1, you can instantiate it this way:

NestedClass1 c = new NestedClass1();