Troubles implementing IEnumerable

Question

I\'m trying to write my own (simple) implementation of List. This is what I did so far:

using System;
using System.Collections.Generic;
using System.Linq;
us         


        

Answer 1

Read the error message more carefully; it is telling you exactly what you must do. You did not implement System.Collections.IEnumerable.GetEnumerator.

When you implement the generic IEnumerable<T> you have to also implement System.Collections.IEnumerable's GetEnumerator.

The standard way to do so is:

public IEnumerator<T> GetEnumerator () { whatever }
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
    return this.GetEnumerator();
}

Answer 2

Add the following method:

IEnumerator IEnumerable.GetEnumerator()
{
    return this.GetEnumerator();
}

Answer 3

There are two overloads of GetEnumerator() that you must implement. One comes from IEnumerable<T> and returns IEnumerator<T>. The other comes from IEnumerable and returns IEnumerator. The override should look like this:

IEnumerator IEnumerable.GetEnumerator()

This is because IEnumerable<T> implements IEnumerable.

Answer 4

Since your class, MyList<T> inherits IEnumerable<out T> which in turn inherits the non-generic IEnumerable, you have two methods you need to implement:

IEnumerator<T> IEnumerable<T>.GetEnumerator()
        {
            throw new NotImplementedException();
        }

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            throw new NotImplementedException();
        }

An easy way to do this is when you declare your class:

class MyList<T> : IEnumerable<T>

Right click the IEnumerable<T> text and select Implement Interface > Implement Interface Explictly from the context menu.

Answer 5

You'll need to implement the non-generic GetEnumerator method as well:

IEnumerator IEnumerable.GetEnumerator()
{
    return GetEnumerator();
}

Since the IEnumerable<T> interface extends IEnumerable, you have to implement the methods declared on both.

Answer 6

I got similar problem,though I implemented also IEnumerable and IEnumerable. I was using custom type (Person class) than generic type T. For me the reason was, namespace was not included in the top of file.

using System.Collections; 

After adding the namespace it was fine for me.