/?Column=ColumnName&Direction=Ascending

Html.ActionLink("View 10", "Index", new { pageSize = 10 })

/?PageSize=10

/?Column=ColumnName&Direction=Ascending&PageSize=10

Html.ActionLink(
    "View 10",
    "Index",
    new {
        Column = Request["Column"],
        Direction = Request["Direction"],
        pageSize = 10
    }
)

Html.PaginateLink("View 10", 10)

public static class HtmlExtensions
{
    public static MvcHtmlString PaginateLink(
        this HtmlHelper helper,
        string linkText,
        int pageSize
    )
    {
        var query = helper.ViewContext.HttpContext.Request.QueryString;
        var values = query.AllKeys.ToDictionary(key => key, key => (object)query[key]);
        values["pageSize"] = pageSize;
        var routeValues = new RouteValueDictionary(values);
        return helper.ActionLink(linkText, "Index", routeValues);
    }
}