how-to pass the reference of the current instance in C#

Question

e.g. something like ( ref this ) which does not work ... E.g. this fails:

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

namespace CopyOfThis
{
    class Program
    {
        static void Main(string[] args)
        {
            View objView = new View();
            objView.Boo();
            objView.ShowMsg("The objView.StrVal is " + objView.StrVal);
            Console.Read();
        }
    } //eof Program


    class View
    {
        private string strVal;
        public string StrVal
        {
            get { return strVal; }
            set { strVal = value; } 

        }
        public void Boo()
        {
            Controller objController = new Controller(ref this);
        }

        public void ShowMsg ( string msg ) 
        {
            Console.WriteLine(msg); 
        }


    } //eof class 

    class Controller
    {
        View View { get; set; } 
        public Controller(View objView)
        {
            this.View = objView;
            this.LoadData();
        }

        public void LoadData()
        {
            this.View.StrVal = "newData";
            this.View.ShowMsg("the loaded data is" + this.View.StrVal); 
        }
    } //eof class 

    class Model
    { 

    } //eof class 
} //eof namespace 

Answer 1

this is already a reference. Code like

DoSomethingWith(this);

is passing the reference to the current object to the method DoSomethingWith.

Answer 2

Remember that the variable passed as ref should be initialized before.

Answer 3

You can't change this reference.

Answer 4

I think I follow you, so I'll do my best to answer.

this is already a reference to the current instance, so if you want to pass around a reference to the current instance you can do the following:

myClass.MyMethod(this);

However, if you wanted to pass around a copy of the "this" reference (rather than the instance it is referencing), you would need to copy it to another reference first:

var copyOfThis = this;
myClass.MyMethod(ref copyOfThis);

This is because you can't actually pass this directly as a ref. this always points to the current instance, so it makes no sense to be able to pass around the reference itself.

Answer 5

EDIT: Given your edited code example, you don't need to pass ref this since as the accepted answer states - this is already a reference.

you can't pass the this reference by reference because it is constant; passing it by ref would allow it to be changed - which is nonsense as far as C# is concerned.

The closest you can get is to do:

var this2 = this;
foo(ref this2);

Answer 6

If you have a method like this:

void Foo(ref Bar value) {
  // bla bla
}

You can call it from a Bar object by creating a temporary variable like this

var temp = this;
foo.Foo(ref temp);