Passing a reference argument using ref

Passing a reference argument using ref

• Sam_res03

  Thanks,

  I will think about what you have said and will I read through the url article before asking any further questions.

  Regards

  Andrew.

  
  

• xishan shigri

  Related to your topic, I made a simple sample as following:

  namespace Work8

  {

  public class Root

  {

  private static string lang;

  static Root() { lang = "default"; }

  public string Language

  {

  get { return lang; }

  set { lang = value; }

  }

  public virtual void Show()

  {

  System.Console.WriteLine( "Root language {0}", this.Language );

  }

  }

  public class Sister

  {

  public Root root;

  public Sister() { this.root = null; }

  public Sister(ref Root aRoot) { this.root = aRoot; }

  }

  public class Child : Root

  {

  public string Parent

  {

  get { return base.Language; }

  set { base.Language = value; }

  }

  public override void Show()

  {

  System.Console.WriteLine( "Parent language {0}",this.Parent);

  }

  }

  class Program

  {

  static void Main()

  {

  Root root = new Root();

  root.Show(); // "Root language default"

  Child child = new Child();

  child.Show(); // "Parent language default"

  Root x = child;

  child.Language = "CSharp";

  Sister sister = new Sister( ref x );

  sister.root.Show(); // "Parent language CSharp"

  sister.root.Language = "Basic";

  root.Show(); // "Root language Basic"

  System.Console.ReadKey();

  }

  }

  }

  Now a have question related to class Sister constructor. How can I modify code so there is no explicit reference to class Root and a general variable to hold reference, not like now: public Root root;

  It would be nice if class Sister constructor can get anonymous reference.

  
  
  

• Predator14567

  Sorry, the whole code was a technical joke, without any real usage. It's sole purpose was test that 'ref' parameter passing. The 'static' case is peculiar, but C# can cope with it anyway and it's meaning was to use static constructor here. Anyway, that a little code demonstrates overloading, properties, inheritance, calling by reference etc.
  
  

• gshaf

  Insignia wrote:

  I am having problems with conversion error messages when trying to pass references of derived classes. i.e B b = new B(ref D) the compiler says that it cannot convert D to A Is it possible to pass a reference object by reference when the object is a derivative (like above )

  You have to use a temp variable in that case

  A a = D;

  B b = new B(ref a);

  Insignia wrote:

  If I pass an object of D without using ref , I realise that B will not be able to modify D (due to a copy of the reference D). Is it correct to say that if a reference to object D is passed without using ref, then (a copy) of the entire object D will be passed to B. Is this right

  No, only a copy of the reference. See http://www.yoda.arachsys.com/csharp/parameters.html

  
  
  

• gokce

  It's pretty odd to have an instance property (Root.Language) backed by a static field. It gives clients a rather unexpected behavior.

  I'm not sure what you mean when you say you don't want to have an explicit reference to Root. But if you don't want to strongly type the parameter, you can replace it with an interface it implements (in this case Root doesn't implement any interface) or use System.Object as the type.

  Finally, I don't see any reason for the parameter to the Sister contructor to be a ref parameter.

  
  
  
• Passing a reference argument using ref