C# Pagination inspired by @jorrit91 version (https://gist.github.com/kottenator/9d936eb3e4e3c3e02598#gistcomment-3238804) of simple-pagination.js (https://gist.github.com/kottenator/9d936eb3e4e3c3e02598)

Pagination.cs

public IEnumerable<object> Pages(int current, int pageCount) {
    List<object> pages = new List<object>();
    var delta = 7;

    if (pageCount > 7) {
            delta = current > 4 && current < pageCount - 3 ? 2 : 4;
    }

    var startIndex = (int)Math.Round(current - delta / (double)2);
    var endIndex = (int)Math.Round(current + delta / (double)2);

    if (startIndex - 1 == 1 || endIndex + 1 == pageCount) {
            startIndex += 1;
            endIndex += 1;
    }

    var to = Math.Min(pageCount, delta + 1);
    for (int i = 1; i <= to; i++) {
            pages.Add(i);
    }

    if (current > delta) {
            pages.Clear();
            var from = Math.Min(startIndex, pageCount - delta);
            to = Math.Min(endIndex, pageCount);
            for (int i = from; i <= to; i++) {
                    pages.Add(i);
            }
    }

    if (pages[0].ToString() != "1") {
            if (pages.Count() + 1 != pageCount) {
                    pages.Insert(0, "...");
            }
            pages.Insert(0, 1);
    }

    if ((int)pages.Last() < pageCount) {
            if (pages.Count() + 1 != pageCount) {
                    pages.Add("...");
            }
            pages.Add(pageCount);
    }

    return pages;
}