ListPagerRazorLibrary

This a set of Asp Net Core 3.0 View Components, Partial Views and related statics (css/js), styled with Bootstrap 4 and wrapped in a Razor Class Library.

It provides composable and stylable pager UI, paging event triggering and related paging-event scripting. It is agnostic about data source, sorting, etc.

Your pager can be composed using the library's View Components and/or Partial Views, configured using the provided ListPagerModel and styled with CSS.

The library includes predefined base, dark and neon themes which can be overridden or customized.

See below for detailed description of library content and customization/override information.

Bootstrap Note

This is a Bootstrap 4 styled library. If you have a need for another styling library (e.g Bulma) I'd suggest that you fork the project.

Javascript Note

The Library itself uses vanilla javascript (no JQuery or other libs) with the exception of ListPagerDropDown which at V00.01.00Beta requires the Bootstrap 4 JS library bundle (including popper.js).

If you don't want to include that library in your project, you can simply set the ListPagerModel.ShowDropdown to false. The standard ListPager will not display the dropdown.

The library is otherwise agnostic about JS framework, provided that it is event-aware.

Setup

To use ListPager in your Asp.Net Core (3.0 or later) Web project :

Add a reference to the ListPagerRazorLibrary project or DLL. At this writing (10/2020) the library is not available on NuGet. Download/ clone / fork the library and include it or it's DLL in your solution.

In the host project's _ViewImports.cshtml add these lines:

@using ListPagerRazorLibrary
@using ListPagerRazorLibrary.Models
@using ListPagerRazorLibrary.ViewComponents

In the host project's _Layout.cshtml page include

<link rel="stylesheet" href="/_content/ListPagerRazorLibrary/css/pager.css" />

or, one of the predefined themes

<link rel="stylesheet" href="/_content/ListPagerRazorLibrary/css/pager-dark.css" />

<link rel="stylesheet" href="/_content/ListPagerRazorLibrary/css/pager-neon.css" />

or, create your own

Examples

Please see the working examples in the examples project for implementation details in full page POST and GET scenarios, as well as different AJAX scenarios.

Customizing & Overriding

For our purposes here, overriding refers to placing replacement files in the path that Dot Net expects to find them, entirely overriding the related library object, whether .cshtml or .css while customizing refers altering appearance or behaviour without overriding an entire library file.

There are several ways to alter the pager's appearance and/or behaviour. These are demonstraed in the "examples' project but in summary, you can :

Use the visibility toggles and other settings available in the provided ListPagerModel c# Class (see below)
Override a library view (e.g. 'ListPagerPageOf.cshtml') by adding your own version to your project (see path placement below)
Override the CSS in wwwroot/css/*.css' and/or include your own .css file(s)
Change the layout/ by composing your own container View Component, ignoring or overriding ListPager.cshtml / _ListPager.cshtml

override file placement

At this writing RCL file-level overrides require that the host folder structure mirror the library's structure. ListPagerRazorLibrary has the following relevant structure:

Pages/Shared (Partial View containers live here)
Pages/Shared/Components (all Component Views reside here)
wwwroot/css/pager.css (base theme)
wwwroot/css/pager-dark.css (darkness)
wwwroot/css/pager-neon.css (gloriously gaudy)

So, to override say, the ListPagerLinks.cshtml View Component with your own version, place your version in your project at:

/pages/Shared/Components/ListPagerLinks.cshtml

Overriding wwwroot/js/pager.js will work but is not recommended. I'd suggest forking the project instead, unless you are comfortable handling any library future changes that impact the scripting.

User CSS

Whether you use the library's CSS files or override them, you can also include your own files as normal, to override specific selector definitions.

CSS Classes

The RCL static resource "pager.css" (and the themed files) assigns some of its own class names:

li.page-item
li.page-item.disabled
li.page-item.pager-range
a.page-link
a.page-link.disabled
span.pager-page
span.pager-dropdown

If I've missed any please let me know

Partial Views In The Library

The library is primarily a View Component library and while any of the View Components can be invoked as Partial Views, the library also contains these "View Component free" Partial Views:

_ListPagerShort

Implements the pager as a simple range (ul) of page numbers and elipses that provide movement up and down the full range of data pages.

_ListPagerSheets

Implements the pager in a format suitable for paging through a document, for example a multi-page blog entry, with a fixed pager width.

_ListPager

The fully composed ListPager that implements all of it's features as Partial Views, not View Components.

ListPager View Components as Partial Views

With the caveats below you can also use any of the library's View Components as Partial Views.

For example like this for ListPagerLinks.cshtml:

```
<partial name="Components/ListPagerLinks.cshtml" model="[ModelInstance]" />
            
/* Note - ListPagerArrows and ListPagerDropdown require instances of their own Models,
*  ListPagerArrowModel and ListPagerDropDownModel, and are therefore perhaps best 
*  invoked as ViewComponents where the mode;ls are sintantiated automatically. 
*
*  All other View Components require a ListPagerModel instance which
*  is typically passed to the container ListPager.cstml or _ListPager.cshtml
*   
*  See _ListPager.cshtml and ListPager.cshtml for example usage.
*/
```

Library View Components

View components are provided for each major element of the pager, as well as for the default composition of the Pager itself.

ListPagerArrows

Backward and Forward single and double arrows
Note - requires an instance of ListPagerArrowModel which is automatically instantiated when Invoked as a View Component but must be manually instantiated when used as a Partial View.

ListPagerPageOf

The typical 'Page N of T' display

ListPagerLinks

A series of N linked page numbers
ListPagerModel.MaxPageLinks determines maximum N to be displayed

ListPagerRecords

A 'N of T records' display, suitable for filtered data sets
Typically ListPagerModel.IsFiltered is in use with this

ListPagerDropdown

A configurable drop-down menu of incremental page jumps ListPagerModel.DropDownIncrement determines generated jump increments
Note - requires an instance of ListPagerDropdownModel which is automatically instantiated when Invoked as a View Component but must be manually instantiated when used as a Partial View.
REQUIRES Bootstrap 4 JS dropdown support

ListPagerPageSize

A page-size UI element to allow user-setting of ListPagerModel.PageSize

ListPagerPostForm

For convenience in POST scenarios, includes all ListPagerModel properties

ListPager

the pager itself comes in two flavours both of which can be overridden, typically to change composition and/or Layout:
- Pages/Shared/Components/ListPager.cshtml - uses the above views as View Components
- Pages/Shared/_ListPager.cshtml - uses the above views as Partial Views

ListPagerModel C# Class

ListPagerModel.cs is required to implement the pager. See Examples for implemenation details. In summary it provides the following properties, and single method:

Toggles

The following ListPagerModel Boolean properties are available to trigger display/non-display of individual View Components in the composed Pager.

NOTE that use of the toggles is manual - you must specify their values in your code and, if you are overriding ListPager.cshtml or composing your own pager, you must use them in conditional (if) statements within the composed ListPager to give them effect.

ShowPageOf

Intended to toggle "ListPagerPageOf" display, default false

ShowDropDown

Intended to toggle "ListPagerDropdown" display, default false

ShowRecordsOf

Intended to toggle "ListPagerRecords" display, default false

ShowPageSize

Intended to toggle "ListPagerPageSize" display, default true

Required Method

CheckBoundaries()

The only method in the class, it is importantly responsible for checking/setting page boundaries and ListPagerModel.PageCount.
IMPORTANT - there is intentionally no other setter for ListPagerModel.PageCount as it is imperative that you call this prior to returning data or a view.

Other User-Settable Properties

TotalRecords

Total unfiltered records in the dataset, as in: myDataSet.Count()
CheckBoundaries() will set this to '0' if you leave it null

MaxPageLinks

Maximum number of page-numbered links in the ListPagerLinks.cshtml view

PageSize

Rows per page, used in the ListPagerPageSize.cshtml view

MaxPageSize

Maximum value for the Page Size ui input, enforced by the ListPagerModel.PageSize setter.

MinPageSize

Minimum value for the Page Size ui input, enforced by the ListPagerModel.PageSize setter.

PageSizeInputId

DOM id of the Page Size input box living in the ListPagerPageSize view

PostTarget

The URL target to POST ListPagerPostForm to, not required if you are not using that form

DropDownIncrement

The increment between page number links in the ListPagerDropdown view

Sort State

for convenience if you are providing a single column sort, you can carry its state in these ListPagerModel props
- SortDirection
- SortColumn

Other Properties

PageCount

No public setter, this can only be set by calling the CheckBoundaries() method

PageNumber

Technically you can set this, but you should always ask pager.js instead, via client Pager State, with pager.goToPage(N) which fires a paging event.
WARNING - the pager.js setActivePage(N) method results in a direct UI update, no paging event is issued. It may be deprecated in a future version.

FilteredRecordCount

Defaults to TotalRecordCount if null. It impacts the IsFiltered flag which is typically used to determine ListPagerModel.ShowRecordsOf state (i.e. toggle the ListPagerRecords view)

IsFiltered

No setter - Getter returns a comparison of the ListPagerModel.TotalRecords and ListPagerModel.FilteredRecordCount property values

Pull Requests and Maintenance

Any errors or omissions please do let me know.

I may or may not update this over time, but requests or suggestions are also welcome.

Credits

Thanks to @ianbusko for this (Dot Net 2.0) head start: https://github.com/ianbusko/reusable-components-library

glburman/ListPagerRazorLibrary