Add parameter using PagedList in record detail and page links

The PagedList documentation or the X.PagedList (the latest version) suggests something like this:

@Html.PagedListPager((IPagedList)Model, page => Url.Action("Index", new { pag = page }) )

This is a common problem ( I wrote a course that I teach to solve it and more some others , by the way). The problem is not the paging itself, but the search parameters are not preserved when detailing the record or going to a different page.

To resolve, you need to implement two extensions : one for HtmlHelper and another one for the UrlHelper ". These are:

HtmlHelperExtensions

public static class HtmlHelperExtensions
{
    /// <summary>
    /// 
    /// </summary>
    /// <param name="htmlHelper"></param>
    /// <param name="linkText"></param>
    /// <param name="action"></param>
    /// <returns></returns>
    public static string ActionQueryLink(this HtmlHelper htmlHelper,
        string linkText, string action)
    {
        return ActionQueryLink(htmlHelper, linkText, action, null);
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="htmlHelper"></param>
    /// <param name="linkText"></param>
    /// <param name="action"></param>
    /// <param name="routeValues"></param>
    /// <returns></returns>
    public static string ActionQueryLink(this HtmlHelper htmlHelper,
        string linkText, string action, object routeValues)
    {
        var queryString =
            htmlHelper.ViewContext.HttpContext.Request.QueryString;

        var newRoute = routeValues == null
            ? htmlHelper.ViewContext.RouteData.Values
            : new RouteValueDictionary(routeValues);

        foreach (string key in queryString.Keys)
        {
            if (!newRoute.ContainsKey(key))
                newRoute.Add(key, queryString[key]);
        }
        return HtmlHelper.GenerateLink(htmlHelper.ViewContext.RequestContext,
            htmlHelper.RouteCollection, linkText, null /* routeName */,
            action, null, newRoute, null);
    }
    public static string ActionReferrerQuery(this HtmlHelper htmlHelper,
        string linkText, string action, string controller, object routeValues)
    {
        var referrer = htmlHelper.ViewContext.HttpContext.Request.UrlReferrer;
        if (referrer.Query == null) return HtmlHelper.GenerateLink(htmlHelper.ViewContext.RequestContext,
            htmlHelper.RouteCollection, linkText, "Default", action, controller, null, null);

        var queryString = referrer.Query.Replace("?", "");

        var newRoute = routeValues == null
            ? htmlHelper.ViewContext.RouteData.Values
            : new RouteValueDictionary(routeValues);

        if (!string.IsNullOrEmpty(queryString))
        {
            foreach (string key in queryString.Split('&'))
            {
                var keyValuePair = key.Split('=');
                if (!newRoute.ContainsKey(keyValuePair[0]))
                    newRoute.Add(keyValuePair[0], keyValuePair[1]);
            }
        }

        return HtmlHelper.GenerateLink(htmlHelper.ViewContext.RequestContext,
            htmlHelper.RouteCollection, linkText, "Default", action, controller, newRoute, null);
    }
}

UrlHelperExtensions

public static class UrlHelperExtensions
{
    public static string ActionQuery(this UrlHelper urlHelper,
        string action, string controller)
    {
        return ActionQuery(urlHelper, action, controller, null);
    }

    public static string ActionQuery(this UrlHelper urlHelper,
        string action, string controller, object routeValues)
    {
        var queryString =
            urlHelper.RequestContext.HttpContext.Request.QueryString;

        var newRoute = routeValues == null
            ? urlHelper.RequestContext.RouteData.Values
            : new RouteValueDictionary(routeValues);

        foreach (string key in queryString.Keys)
        {
            if (!newRoute.ContainsKey(key))
                newRoute.Add(key, queryString[key]);
        }

        return UrlHelper.GenerateUrl("Default", action, controller, newRoute, 
            urlHelper.RouteCollection, urlHelper.RequestContext, true);
    }

    public static string ActionReferrerQuery(this UrlHelper urlHelper,
        string action, string controller, object routeValues)
    {
        var referrer = urlHelper.RequestContext.HttpContext.Request.UrlReferrer;
        if (referrer.Query == null) return UrlHelper.GenerateUrl("Default", action, controller, null,
            urlHelper.RouteCollection, urlHelper.RequestContext, true);

        var queryString = referrer.Query.Replace("?", "");

        var newRoute = routeValues == null
            ? urlHelper.RequestContext.RouteData.Values
            : new RouteValueDictionary(routeValues);

        if (!string.IsNullOrEmpty(queryString))
        {
            foreach (string key in queryString.Split('&'))
            {
                var keyValuePair = key.Split('=');
                if (!newRoute.ContainsKey(keyValuePair[0]))
                    newRoute.Add(keyValuePair[0], keyValuePair[1]);
            }
        }

        return UrlHelper.GenerateUrl("Default", action, controller, newRoute,
            urlHelper.RouteCollection, urlHelper.RequestContext, true);
    }
}

Once you've done this, you can use the link like this:

@Html.PagedListPager((PagedList.IPagedList)Model, page => Url.ActionQuery("MinhaActionDePesquisa", "MeuController", new { pag = page }))

Parameters will be added automatically in pagination.

For Detail View , use the Back button:

<a href="@Url.ActionReferrerQuery("MinhaActionDePesquisa", "MeuController", null)">Voltar para Lista/Pesquisa</a>