如何在asp.net核心中使用分页列表实现多分页？

Question

我是 asp.net 核心的新手。我有一个按年份分组的列表，我想为它们分页子项。我现在可以使用 pagedList 来分页一个简单的列表。非常感谢！

这是我的剃须刀页面：

<ul class="list-group">

    @foreach (var item in Model)
    {

        <li class="d-flex border-0 bg-transparent">
            @item.Key
        </li>

        @foreach (var p in item.GroupBy(x => x.KeyA).OrderBy(o => o.Key))
        {

            <li class="d-flex border-0 bg-transparent my-2">
                @p.Key
            </li>


            @foreach (var a in item.Where(x => x.Data.Year == item.Key && x.KeyA == p.Key).OrderBy(o => o.Customer.Name).Select(a => a.Customer).Distinct())
            {
//I would like to paginate thesse items
                <li class="list-group-item d-flex justify-content-between align-items-center border my-1 p-0 pl-2 bg-white">
                    @a.Nome
                    <a asp-action="Details" asp-controller="Animais" asp-route-id="@a.CustomerId" class="btn btn-success btn-sm d-none d-md-block">SEE MORE</a>
                    <a asp-action="Details" asp-controller="Animais" asp-route-id="@a.CustomerId" class="btn btn-success btn-sm d-md-none">
                        <span class="fas fa-eye"></span>
                    </a>
                </li>

            }

        }

    }
</ul>

Answer 1

以下是使用Bootstrap分页的解决方案。

在 ProductController.cs 中：

using System.Linq;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;

namespace TestControllers
{
    public class ProductController : Controller
    {
        private readonly ILogger<ProductController> _logger;

        public ProductController(ILogger<ProductController> logger)
        {
            _logger = logger;
        }

        public IActionResult Products()
        {
            //Generate test products data
            var products = Enumerable.Range(1,1000).Select(i=>
                new Product(){Id=i,BrandId=i%10+1, CategoryId=i%20 + 1, ExpirationDate="12/"+(i%31 + 1) + "/2020", Name="Product"+i, OriginCity="City"+(i%40 + 1), OriginCountry="Country"+(i%50 + 1), ProducerName="Producer"+ i+100 + 1, ProductionDate="1/"+(i%31 + 1) + "/2020"} 
            ).ToList();
            return View(products);
        }
    }

    public class Product
    {
        public int Id { get; set; }
        public int CategoryId { get; set; }
        public int BrandId { get; set; }
        public string Name { get; set; }
        public string ProducerName { get; set; }
        public string OriginCity { get; set; }
        public string OriginCountry { get; set; }
        public string ProductionDate { get; set; }
        public string ExpirationDate { get; set; }
    }


}

在 Product.cshtml 中：

@model List<TestControllers.Product>
@using System.Linq;

@{
    ViewData["Title"] = "Products Page";
    var category = this.Context.Request.Query["category"];
    var page = this.Context.Request.Query["page"];
    var categoryInt = !string.IsNullOrEmpty(category) ? int.Parse(category) : 1;
    var pageInt = !string.IsNullOrEmpty(page) ? int.Parse(page) : 1;
    var productsPerPage = 10;

    //Get pager contents
    Func<string,string, int, int,int, Func<int,Dictionary<string,string>>, string> getPager = (controller,action,pages, currentPage,numberOfPages, getParameters) =>
    {
        //Get query string for a given page number
        Func<int, string> getQueryString = (page1) =>
        {
            var queryString =  getParameters(page1).ToList().Aggregate("", (content, next) =>
            {
                content = !string.IsNullOrEmpty(content) ? content + "&" : content;
                content += string.Format("{0}={1}", next.Key, next.Value);
                return content;
            });
            queryString = !string.IsNullOrEmpty(queryString) ? "?" + queryString : queryString;
            return queryString;
        };
        var pager = "<nav aria-label=\"...\"><ul class=\"pagination .pagination-lg\">";
        if(currentPage>1)
        {
            pager+= "<li class=\"page-item\"><a class=\"page-link\" href=\"" + string.Concat("/", controller, "/", action, getQueryString(currentPage-1)) + "\">Previous</a></li>";
        }
        else
        {
            pager += "<li class=\"page-item disabled\"><span class=\"page-link\">Previous</span></li>";
        }

        var renderedPageSets = new List<List<int>>();
        var renderedPages = 0;
        if(pages<= numberOfPages)
        {
            renderedPageSets.Add(Enumerable.Range(1, pages).ToList());
        }
        else
        {
            while (renderedPages < pages)
            {
                var lastSetPage = renderedPages + numberOfPages;
                if (lastSetPage <= pages)
                {
                    renderedPageSets.Add(Enumerable.Range(++renderedPages, numberOfPages).ToList());
                }
                else
                {
                    renderedPageSets.Add(Enumerable.Range(pages - numberOfPages + 1, numberOfPages).ToList());
                }
                if(renderedPageSets.Last().Contains(currentPage))
                {
                    break;
                }
                renderedPages = lastSetPage;
            }
        }
        var renderedPageSet = renderedPageSets.First(s => s.Contains(currentPage));
        if(renderedPageSet.First()!=1)
        {
            pager += "<li class=\"page-item disabled\"><span class=\"page-link\">...</span></li>";
        }
        pager = renderedPageSet.Aggregate(pager, (currentPagerContent, nextPage) => {
            currentPagerContent += "<li class=\"page-item"+(currentPage==nextPage? " active":"") + " \"><a class=\"page-link\" href=\""+string.Concat("/",controller,"/",action, getQueryString(nextPage)) + "\">"+nextPage+"</a></li>";

            return currentPagerContent;
        });
        if (renderedPageSet.Last() != pages)
        {
            pager += "<li class=\"page-item disabled\"><span class=\"page-link\">...</span></li>";
        }

        if (currentPage < pages)
        {
            pager += "<li class=\"page-item\"><a class=\"page-link\" href=\"" + string.Concat("/", controller, "/", action, getQueryString(currentPage + 1)) + "\">Next</a></li>";
        }
        else
        {
            pager += "<li class=\"page-item disabled\"><span class=\"page-link\">Next</span></li>";
        }

        pager += "</li></ul></nav>";

        return pager;
    };
    }
<div class="text-center">
    <h1 class="display-4">Products</h1>
</div>
<div class="card" style="">
    <div class="card-header">
        <div>
            @{
                var categories = Model.Select(i => i.CategoryId).Distinct().Count();
            }

           <h2>Categories:</h2> @Html.Raw(getPager("Product", "Products", categories, categoryInt, 10, (category1) => { return new Dictionary<string, string>() { { "page", "1" }, { "category", category1.ToString() } }; }))
        </div>

        <h3>Products in category @categoryInt</h3>

    </div>
    <br />
    <a asp-action="Add" asp-controller="Product" class="btn btn-success btn-sm" style="width:148px">Add a New Product</a>
    <table class="table table-bordered">
        <tr>
            <th>Category</th>
            <th>Name</th>
            <th>Producer Name</th>
            <th>Origin City</th>
            <th>Origin Country</th>
            <th>Production Date</th>
            <th>Expiration Date</th>
            <th>&nbsp;</th>
        </tr>
        @foreach (var product in Model.Where(i => i.CategoryId == categoryInt).Skip((pageInt - 1) * productsPerPage).Take(productsPerPage))
        {
            <tr>
                <td>@product.CategoryId</td>
                <td>@product.Name</td>
                <td>@product.ProducerName</td>
                <td>@product.OriginCity</td>
                <td>@product.OriginCountry</td>
                <td>@product.ProductionDate</td>
                <td>@product.ExpirationDate</td>
                <td>
                    <a asp-action="Edit" asp-controller="Product" asp-route-id="@product.Id" class="btn btn-warning btn-sm">Edit</a>
                    <a asp-action="Delete" asp-controller="Product" asp-route-id="@product.Id" class="btn btn-danger btn-sm">Delete</a>
                </td>
            </tr>
        }
    </table>
    <div>
        @{
            var categoryProductsPages = (int)Math.Ceiling(((double)Model.Where(i => i.CategoryId == categoryInt).Count()) / productsPerPage);
        }

        @Html.Raw(getPager("Product", "Products", categoryProductsPages, pageInt, 10, (page1) => { return new Dictionary<string, string>() { { "page", page1.ToString() }, { "category", category } }; }))
    </div>
</div>

结果视图：