Looking at this Microsoft article How to: Write a Copy Constructor (C#) and also this Generic C# Copy Constructor, wouldn't it be best/safe to use a reference to the class instance than to use a plain copy of the instance ?
public class Myclass() { private int[] row; public MyClass(ref MyClass @class) { for(int i = 0; i<@class.row.Length;i++) { this.row[i] = @class.row[i]; } } } What ref actually means:
void Change(SomeClass instance) { instance = new SomeClass(); } void ChangeRef(ref SomeClass instance) { instance = new SomeClass(); } Later...
SomeClass instance = new SomeClass(); Change(instance); //value of instance remains unchanged here ChangeRef(ref instance); //at this line, instance has been changed to a new instance because //ref keyword imports the `instance` variable from the call-site's scope I can't see how this functionality would be useful with respect to a copy constructor.
ref please. What economy are you hoping to make here?ref keyword allows you to do above.Object by nature is reference not a value type. I do not see any good reason what extra advantage you would get doing it. But yes you might get into problems because of it, consider this -
You created an object and passed it with reference to couple of classes and those classes are now having access to the address of reference itself. Now I have got all the powers to go and change the reference itself with another object's reference. If here, another class had this object it is actually working on some stale object and other classes can not see what changes are being made and you are in chaos.
I do not see any use of doing it, rather it is dangerous. It does not sounds like a OO way of writing code to me.
The ref keyword is used when a method should be allowed to change the location of a reference. Reference types always pass their reference into a method (but the location of the reference cannot be modified via assignment). Values types pass their value.
See: Passing Parameters
Example:
void PassingByReference(List<int> collection) { // Compile error since method cannot change reference location // collection = new List<int>(); collection.Add(1); } void ChangingAReference(ref List<int> collection) { // Allow to change location of collection with ref keyword collection = new List<int>(); collection.Add(2); } var collection = new List<int>{ 5 }; // Pass the reference of collection to PassByReference PassingByReference(collection); // collection new contains 1 collection.Contains(5); // true collection.Contains(1); // true // Copy the reference of collection to another variable var tempCollection = collection; // Change the location of collection via ref keyword ChangingAReference(ref collection); // it is not the same collection anymore collection.Contains(5); // false collection.Contains(1); // false // compare the references use the default == operator var sameCollection = collection == tempCollection; // false 
@. Edited, but not advisable.refkeyword actually means, especially when used in conjunction with reference types.MyClass) are always passed by reference.refmeans you are passing a reference to the variable, so if you were to change@classto point to a differentMyClass, the caller would see that happen to whatever variable they passed in.refisn't permitted (properties, anonymous methods, etc.)