Foreach loop, determine which is the last iteration of the loop

Question

I have a foreach loop and need to execute some logic when the last item is chosen from the List, e.g.:

 foreach (Item result in Mod         


        

Answer 1

     List<int> ListInt = new List<int> { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };


                int count = ListInt.Count;
                int index = 1;
                foreach (var item in ListInt)
                {
                    if (index != count)
                    {
                        Console.WriteLine("do something at index number  " + index);
                    }
                    else
                    {
                        Console.WriteLine("Foreach loop, this is the last iteration of the loop " + index);
                    }
                    index++;

                }
 //OR
                int count = ListInt.Count;
                int index = 1;
                foreach (var item in ListInt)
                {
                    if (index < count)
                    {
                        Console.WriteLine("do something at index number  " + index);
                    }
                    else
                    {
                        Console.WriteLine("Foreach loop, this is the last iteration of the loop " + index);
                    }
                    index++;

                }

Answer 2

You can make an extension method specially dedicated to this:

public static class EnumerableExtensions {
    public static bool IsLast<T>(this List<T> items, T item)
        {
            if (items.Count == 0)
                return false;
            T last = items[items.Count - 1];
            return item.Equals(last);
        }
    }

and you can use it like this:

foreach (Item result in Model.Results)
{
    if(Model.Results.IsLast(result))
    {
        //do something in the code
    }
}

Answer 3

".Last()" didnt work for me, so I had to do something like this:

Dictionary<string, string> iterativeDictionary = someOtherDictionary;
var index = 0;
iterativeDictionary.ForEach(kvp => 
    index++ == iterativeDictionary.Count ? 
        /*it's the last item */ :
        /*it's not the last item */
);

Answer 4

To do something additional to each element except for the last one, function based approach can be used.

delegate void DInner ();

....
    Dinner inner=delegate 
    { 
        inner=delegate 
        { 
            // do something additional
        } 
    }
    foreach (DataGridViewRow dgr in product_list.Rows)
    {
        inner()
        //do something
    }
}

This approach has apparent drawbacks: less code clarity for more complex cases. Calling delegates might be not very effective. Troubleshooting might be not quite easy. The bright side - coding is fun!

Having said that, I would suggest using plain for loops in trivial cases, if you know that your collection's count is not terribly slow.

Answer 5

We can check last item in loop.

foreach (Item result in Model.Results)
{
    if (result==Model.Results.Last())
    {
        // do something different with the last item
    }
}

Answer 6

The best approach would probably be just to execute that step after the loop: e.g.

foreach(Item result in Model.Results)
{
   //loop logic
}

//Post execution logic

Or if you need to do something to the last result

foreach(Item result in Model.Results)
{
   //loop logic
}

Item lastItem = Model.Results[Model.Results.Count - 1];

//Execute logic on lastItem here