NOTE: Apart from
(and even then it's questionable, I'm Scottish). These are machine translated in languages I don't read. If they're terrible please contact me.
You can see how this translation was done in this article.
Tuesday, 11 March 2025
//Less than a minute
A work project the other day necessitated implementing paging form results. My go-to paging tag helper has always been the pagination Tag Helper by Darrel O'Neill as I wrote about here however for whatever reason it's just stopped working for me. So instead of trying to puzzle through what looks like an abandoned project at this point I decided to build one myself.
As usual you can get the source for this on my GitHub
I have a sample site for this project hosted here
This has samples of the output like this:
For this tag helper I had a few requirements:
Dafault.cshtml view.In future I'll add the capability to:
The taghelper is now a shiny new Nuget package so you can install it with the following command:
dotnet add package mostlylucid.pagingtaghelper
You'd then add the tag helper to your _ViewImports.cshtml file like so:
@addTagHelper *, mostlylucid.pagingtaghelper
Then you can just start using it; I provide some helper classes which you can use to configre it such as
IPagingModelThis is the 'basic stuff' you need to get started. It's a simple interface that you can implement on your model to get the paging working. Note that ViewType is optional here it defaults to TailwindANdDaisy but you can set it to Custom, Plain or Bootstrap if you want to use a different view.
public enum ViewType
{
TailwindANdDaisy,
Custom,
Plain,
Bootstrap
}
OR you can even specify a custom View by using the TagHelper's use-local-view property.
namespace mostlylucid.pagingtaghelper.Models;
public interface IPagingModel
{
public int Page { get; set; }
public int TotalItems { get; set; }
public int PageSize { get; set; }
public ViewType ViewType { get; set; }
public string LinkUrl { get; set; }
}
namespace mostlylucid.pagingtaghelper.Models;
public interface IPagingSearchModel : IPagingModel
{
public string? SearchTerm { get; set; }
}
I have also implement these in the project to provide a baseline:
public abstract class BasePagerModel : IPagingModel
{
public int Page { get; set; } = 1;
public int TotalItems { get; set; } = 0;
public int PageSize { get; set; } = 10;
public ViewType ViewType { get; set; } = ViewType.TailwindANdDaisy;
public string LinkUrl { get; set; } = "";
}
public abstract class BasePagerSearchMdodel : BasePagerModel, IPagingSearchModel
{
public string? SearchTerm { get; set; }
}
I'll cover the search functionality in a future article..
I then worked out what I would like the TagHelper to look like in use:
<paging
x-ref="pager"
hx-boost="true"
hx-indicator="#loading-modal"
hx-target="#user-list "
hx-swap="show:none"
model="Model"
pages-to-display="10"
hx-headers='{"pagerequest": "true"}'>
</paging>
Here you can see I set a few HTMX parameters and the model to use for the paging. I also set the number of pages to display and the headers to send with the request (this allows me to use HTMX to populate the page).
The component also has a BUNCH of other config elements which I'll work through in future articles. As you can see therer's a LOT of possible configuration.
<paging css-class=""
first-last-navigation=""
first-page-text=""
next-page-aria-label=""
next-page-text=""
page=""
pages-to-display=""
page-size=""
previous-page-text=""
search-term=""
skip-forward-back-navigation=""
skip-back-text=""
skip-forward-text="true"
total-items=""
link-url=""
last-page-text=""
show-pagesize=""
use-htmx=""
use-local-view=""
view-type="Bootstrap"
htmx-target=""
id=""
></paging>
The TagHelper is pretty simple but has a bunch of properties enabling the user to customize the behaviour (you can see this below in the view ) aside from the properties (which I won't paste here for brevity) the code is fairly straightforward:
/// <summary>
/// Processes the tag helper to generate the pagination component.
/// </summary>
/// <param name="context">The tag helper context.</param>
/// <param name="output">The tag helper output.</param>
public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
output.TagName = "div";
//Remove all the properties that are not needed for the rendered content.
output.Attributes.RemoveAll("page");
output.Attributes.RemoveAll("link-url");
output.Attributes.RemoveAll("page-size");
output.Attributes.RemoveAll("total-items");
output.Attributes.RemoveAll("pages-to-display");
output.Attributes.RemoveAll("css-class");
output.Attributes.RemoveAll("first-page-text");
output.Attributes.RemoveAll("previous-page-text");
output.Attributes.RemoveAll("skip-back-text");
output.Attributes.RemoveAll("skip-forward-text");
output.Attributes.RemoveAll("next-page-text");
output.Attributes.RemoveAll("next-page-aria-label");
output.Attributes.RemoveAll("last-page-text");
output.Attributes.RemoveAll("first-last-navigation");
output.Attributes.RemoveAll("skip-forward-back-navigation");
output.Attributes.RemoveAll("model");
output.Attributes.RemoveAll("show-pagesize");
output.Attributes.RemoveAll("pagingmodel");
output.Attributes.RemoveAll("use-local-view");
var pagerId = PagerId ?? $"pager-{Guid.NewGuid():N}";
var linkUrl = LinkUrl ?? ViewContext.HttpContext.Request.Path;
PageSize = Model?.PageSize ?? PageSize ?? 10;
Page = Model?.Page ?? Page ?? 1;
ViewType = Model?.ViewType ?? ViewType;
TotalItems = Model?.TotalItems ?? TotalItems ?? 0;
if(Model is IPagingSearchModel searchModel)
SearchTerm = searchModel?.SearchTerm ?? SearchTerm ?? "";
output.Attributes.SetAttribute("id", pagerId);
var viewComponentHelper = (IViewComponentHelper)ViewContext.HttpContext.RequestServices.GetService(typeof(IViewComponentHelper))!;
((IViewContextAware)viewComponentHelper).Contextualize(ViewContext);
var pagerModel = PagerModel ?? new PagerViewModel()
{
ViewType = ViewType,
UseLocalView = UseLocalView,
UseHtmx = UseHtmx,
PagerId = pagerId,
SearchTerm = SearchTerm,
ShowPageSize = ShowPageSize,
Model = Model,
LinkUrl = linkUrl,
Page = Page,
PageSize = PageSize,
TotalItems = TotalItems,
PagesToDisplay = PagesToDisplay,
CssClass = CssClass,
FirstPageText = FirstPageText,
PreviousPageText = PreviousPageText,
SkipBackText = SkipBackText,
SkipForwardText = SkipForwardText,
NextPageText = NextPageText,
NextPageAriaLabel = NextPageAriaLabel,
LastPageText = LastPageText,
FirstLastNavigation = FirstLastNavigation,
SkipForwardBackNavigation = SkipForwardBackNavigation,
HtmxTarget = HtmxTarget,
};
var result = await viewComponentHelper.InvokeAsync("Pager", pagerModel);
output.Content.SetHtmlContent(result);
}
It comprises of these steps:
div; this is the container for the pager.IPagingModel and have the pager work with no further configuration.PagerViewModel with the properties set to the values we have or the defaults if not provided.Pager ViewComponent with the PagerViewModel and set the output content to the result.Again all pretty simple.
The view for the ViewComponent is pretty simple; it's just a loop through the pages and a few links to the first, last, next and previous pages.
@model mostlylucid.pagingtaghelper.Components.PagerViewModel
@{
var totalPages = (int)Math.Ceiling((double)Model.TotalItems! / (double)Model.PageSize!);
var pageSizes = new List<int>();
if (Model.ShowPageSize)
{
// Build a dynamic list of page sizes.
// Fixed steps as a starting point.
int[] fixedSteps = { 10, 25, 50, 75, 100, 125, 150, 200, 250, 500, 1000 };
// Add only those fixed steps that are less than or equal to TotalItems.
foreach (var step in fixedSteps)
{
if (step <= Model.TotalItems)
{
pageSizes.Add(step);
}
}
// If TotalItems is greater than the largest fixed step,
// add additional steps by doubling until reaching TotalItems.
if (Model.TotalItems > fixedSteps.Last())
{
int next = fixedSteps.Last();
while (next < Model.TotalItems)
{
next *= 2;
// Only add if it doesn't exceed TotalItems.
if (next < Model.TotalItems)
{
pageSizes.Add(next);
}
}
// Always include the actual TotalItems as the maximum option.
if (!pageSizes.Contains(Model.TotalItems.Value))
{
pageSizes.Add(Model.TotalItems.Value);
}
}
}
}
@if (totalPages > 1)
{
<div class="@Model.CssClass flex items-center justify-center" id="pager-container">
@if (Model.ShowPageSize)
{
var pagerId = Model.PagerId;
var htmxAttributes = Model.UseHtmx
? $"hx-get=\"{Model.LinkUrl}\" hx-trigger=\"change\" hx-include=\"#{pagerId} [name='page'], #{pagerId} [name='search']\" hx-push-url=\"true\""
: "";
<!-- Preserve current page -->
<input type="hidden" name="page" value="@Model.Page"/>
<input type="hidden" name="search" value="@Model.SearchTerm"/>
<input type="hidden" class="useHtmx" value="@Model.UseHtmx.ToString().ToLowerInvariant()"/>
if (!Model.UseHtmx)
{
<input type="hidden" class="linkUrl" value="@Model.LinkUrl"/>
}
<!-- Page size select with label -->
<div class="flex items-center mr-8">
<label for="pageSize-@pagerId" class="text-sm text-gray-600 mr-2">Page size:</label>
<select id="pageSize-@pagerId"
name="pageSize"
class="border rounded select select-primary select-sm pt-0 mt-0 min-w-[80px] pr-4"
@Html.Raw(htmxAttributes)>
@foreach (var option in pageSizes.ToList())
{
var optionString = option.ToString();
if (option == Model.PageSize)
{
<option value="@optionString" selected="selected">@optionString</option>
}
else
{
<option value="@optionString">@optionString</option>
}
}
</select>
</div>
}
@* "First" page link *@
@if (Model.FirstLastNavigation && Model.Page > 1)
{
var href = $"{Model.LinkUrl}?page=1&pageSize={Model.PageSize}";
if (!string.IsNullOrEmpty(Model.SearchTerm))
{
href += $"&search={Model.SearchTerm}";
}
<a class="btn btn-sm"
href="@href">
@Model.FirstPageText
</a>
}
@* "Previous" page link *@
@if (Model.Page > 1)
{
var href = $"{Model.LinkUrl}?page={Model.Page - 1}&pageSize={Model.PageSize}";
if (!string.IsNullOrEmpty(Model.SearchTerm))
{
href += $"&search={Model.SearchTerm}";
}
<a class="btn btn-sm"
href="@href">
@Model.PreviousPageText
</a>
}
@* Optional skip back indicator *@
@if (Model.SkipForwardBackNavigation && Model.Page > Model.PagesToDisplay)
{
<a class="btn btn-sm btn-disabled">
@Model.SkipBackText
</a>
}
@* Determine visible page range *@
@{
int halfDisplay = Model.PagesToDisplay / 2;
int startPage = Math.Max(1, Model.Page.Value - halfDisplay);
int endPage = Math.Min(totalPages, startPage + Model.PagesToDisplay - 1);
startPage = Math.Max(1, endPage - Model.PagesToDisplay + 1);
}
@for (int i = startPage; i <= endPage; i++)
{
var href = $"{Model.LinkUrl}?page={i}&pageSize={Model.PageSize}";
if (!string.IsNullOrEmpty(Model.SearchTerm))
{
href += $"&search={Model.SearchTerm}";
}
<a data-page="@i" class="btn btn-sm mr-2 @(i == Model.Page ? "btn-active" : "")"
href="@href">
@i
</a>
}
@* Optional skip forward indicator *@
@if (Model.SkipForwardBackNavigation && Model.Page < totalPages - Model.PagesToDisplay + 1)
{
<a class="btn btn-sm btn-disabled mr-2">
@Model.SkipForwardText
</a>
}
@* "Next" page link *@
@if (Model.Page < totalPages)
{
var href = $"{Model.LinkUrl}?page={Model.Page + 1}&pageSize={Model.PageSize}";
if (!string.IsNullOrEmpty(Model.SearchTerm))
{
href += $"&search={Model.SearchTerm}";
}
<a class="btn btn-sm mr-2"
href="@href"
aria-label="@Model.NextPageAriaLabel">
@Model.NextPageText
</a>
}
@* "Last" page link *@
@if (Model.FirstLastNavigation && Model.Page < totalPages)
{
var href = $"{Model.LinkUrl}?page={totalPages}&pageSize={Model.PageSize}";
if (!string.IsNullOrEmpty(Model.SearchTerm))
{
href += $"&search={Model.SearchTerm}";
}
<a class="btn btn-sm"
href="@href">
@Model.LastPageText
</a>
}
<!-- Page info text with left margin for separation -->
<div class="text-sm text-neutral-500 ml-8">
Page @Model.Page of @totalPages (Total items: @Model.TotalItems)
</div>
</div>
}
This is broken up into a few sections:
One thing I was missing from the original tag helper was a page size dropdown.
This is a simple select list, you can see I first start out by defining fixedSteps which are just a few fixed steps I want to use for the dropdown. I then loop through these and add them to the list. A habit I always have is having an 'all' option so I add the total items to the list if it's not already there.
@{
var totalPages = (int)Math.Ceiling((double)Model.TotalItems! / (double)Model.PageSize!);
var pageSizes = new List<int>();
if (Model.ShowPageSize)
{
// Build a dynamic list of page sizes.
// Fixed steps as a starting point.
int[] fixedSteps = { 10, 25, 50, 75, 100, 125, 150, 200, 250, 500, 1000 };
// Add only those fixed steps that are less than or equal to TotalItems.
foreach (var step in fixedSteps)
{
if (step <= Model.TotalItems)
{
pageSizes.Add(step);
}
}
// If TotalItems is greater than the largest fixed step,
// add additional steps by doubling until reaching TotalItems.
if (Model.TotalItems > fixedSteps.Last())
{
int next = fixedSteps.Last();
while (next < Model.TotalItems)
{
next *= 2;
// Only add if it doesn't exceed TotalItems.
if (next < Model.TotalItems)
{
pageSizes.Add(next);
}
}
// Always include the actual TotalItems as the maximum option.
if (!pageSizes.Contains(Model.TotalItems.Value))
{
pageSizes.Add(Model.TotalItems.Value);
}
}
}
}
I then render this out to the page
@if (Model.ShowPageSize)
{
var pagerId = Model.PagerId;
var htmxAttributes = Model.UseHtmx
? $"hx-get=\"{Model.LinkUrl}\" hx-trigger=\"change\" hx-include=\"#{pagerId} [name='page'], #{pagerId} [name='search']\" hx-push-url=\"true\""
: "";
<!-- Preserve current page -->
<input type="hidden" name="page" value="@Model.Page"/>
<input type="hidden" name="search" value="@Model.SearchTerm"/>
<input type="hidden" class="useHtmx" value="@Model.UseHtmx.ToString().ToLowerInvariant()"/>
if (!Model.UseHtmx)
{
<input type="hidden" class="linkUrl" value="@Model.LinkUrl"/>
}
<!-- Page size select with label -->
<div class="flex items-center mr-8">
<label for="pageSize-@pagerId" class="text-sm text-gray-600 mr-2">Page size:</label>
<select id="pageSize-@pagerId"
name="pageSize"
class="border rounded select select-primary select-sm pt-0 mt-0 min-w-[80px] pr-4"
@Html.Raw(htmxAttributes)>
@foreach (var option in pageSizes.ToList())
{
var optionString = option.ToString();
if (option == Model.PageSize)
{
<option value="@optionString" selected="selected">@optionString</option>
}
else
{
<option value="@optionString">@optionString</option>
}
}
</select>
</div>
}
You can see I optionally use some HTMX attributes to pass the page size to the server and update the page while retaining the current page and search parameter (if any).
Additionally if you specif use-htmx=false as a parameter on the tag helper it won't output these but instead will allow you to use some JS I provide as an HTML Helper to update the page size.
@Html.PageSizeOnchangeSnippet()
This is a simple script that will update the page size and reload the page (note this doesn't yet work for Plain CSS / Bootstrap as I need to work out the property names etc).
document.addEventListener("DOMContentLoaded", function () {
document.body.addEventListener("change", function (event) {
const selectElement = event.target.closest("#pager-container select[name='pageSize']");
if (!selectElement) return;
const pagerContainer = selectElement.closest("#pager-container");
const useHtmxInput = pagerContainer.querySelector("input.useHtmx");
const useHtmx = useHtmxInput ? useHtmxInput.value === "true" : true; // default to true
if (!useHtmx) {
const pageInput = pagerContainer.querySelector("[name='page']");
const searchInput = pagerContainer.querySelector("[name='search']");
const page = pageInput ? pageInput.value : "1";
const search = searchInput ? searchInput.value : "";
const pageSize = selectElement.value;
const linkUrl = pagerContainer.querySelector("input.linkUrl").value ?? "";
const url = new URL(linkUrl, window.location.origin);
url.searchParams.set("page", page);
url.searchParams.set("pageSize", pageSize);
if (search) {
url.searchParams.set("search", search);
}
window.location.href = url.toString();
}
});
});
The HTMX integration is pretty simple as HTMX is cascading to child elements we can define the HTMX parameters on the parent element and they will be inherited.
hx-boost="true" - this uses the nifty hx-boost feature to intercept the click event and send the request via HTMX.This is pretty simple and uses DaisyUI, boxicons and Tailwind to create a simple loading modal.
<div id="loading-modal" class="modal htmx-indicator">
<div class="modal-box flex flex-col items-center justify-center">
<h2 class="text-lg font-semibold">Loading...</h2>
<i class="bx bx-loader bx-spin text-3xl mt-2"></i>
</div>
</div>
hx-indicator="#loading-modal" then specifies that when an HTMX request is performed it shoould show then hide this modal.
So that's part 1, there's obviously a LOT more to cover and I will in future articles; including the sample site, alternative views, the search functionality and the custom CSS.