Question

I’ve got this MustInherit class called ViewerElement, from which derive classes like ViewerLine, ViewerImage, etc.

Then, in the main program I have a collection of different elements (Images, Lines, etc.). What I want to do is something like the following:

Dim NewElement As ViewerElement
For Each Element As ViewerElement In Elements
    If blabla Then
        NewElement = Element.Clone()
        Exit For
    End If
Next
Elements.Add(NewElement)

I’m getting desperate to implement this Clone method without getting errors. How should this be de done?

Thanks a lot in advance.

Answer 1

You should make ViewerElement implement IClonable interface.
Then, in Clone() method you should create a new ViewerElement object copying all properties values (or changing them according to your needs).
Clone() method must return an object that can be casted with your type; then it’s up to to you decide which values assume properties, wchis status has every single internal variable.

An example (written in C#)

public class ViewerElement : ICloneable
{
    private int a = 0;
    private string b = "";

    public ViewerElement(int a, string b)
    {
        this.a = a;
        this.b = b;
    }

    public object Clone()
    {
        return new ViewerElement(a, b);
    }
}