Question

The .Last() method for Lists only returns a value. I would like to be able to do something like this.

  List<int> a = new List<int> { 1, 2, 3 };
  a.Last() = 4;

This is my attempt at writing an extension method (it does not compile)

public unsafe static T* mylast<T>(this List<T> a)
{
   return &a[a.Count - 1];
}

Is what I want to do possible?

edit:

This is an example of where I would want to use it.

 shapes.last.links.last.points.last = cursor;   //what I want the code to look like
 //how I had to write it.
 shapes[shapes.Count - 1].links[shapes[shapes.Count - 1].links.Count - 1].points[shapes[shapes.Count - 1].links[shapes[shapes.Count - 1].links.Count - 1].points.Count-1] = cursor;

This is why doing

shapes[shapes.Count-1] 

isn’t really a solution.

Answer 1

I’d recommend Thom Smith’s solution, but if you’d really like to have property-like access, why not just use a property?

public class MyList<T> : List<T>
{
    public T Last
    {
        get
        {
            return this[this.Count - 1];
        }
        set
        {
            this[this.Count - 1] = value;
        }
    }
}

Used like:

var m = new MyList<int> { 1, 2, 3 };
m.Last = 4;
Console.WriteLine(m.Last);

No unsafe code, so it’s better. Also, it doesn’t preclude the use of LINQ’s Last method (the compiler can tell the two apart due to how they’re used).