ASP.NET CORE将ID传递给控制器​​以显示页面

时间:2017-08-24 09:08:18

标签: c# asp.net-core asp.net-core-mvc

我正在尝试使用DbContext在页面中显示我的数据。

这是我的控制器:

  public async Task<IActionResult> Index(int? page)
    {
        int _page;
        if (page.HasValue)
        {
            _page = page.Value;
        }
        else
            _page = 1;
        return View(await _context.Agent.Skip(_page-1).Take(10).ToListAsync());

我的布局页面包含链接:

 <li><a asp-area="" asp-controller="Agents" asp-action="Index" asp-route-id="1" >סוכן</a></li>

两件事:

A)它似乎不起作用,无论我在asp-route-id中传递的是同一个列表。我做错了什么?

B)工作完成后,如何呈现供用户选择的页面? (E.G.1,2,3..90)

感谢。

2 个答案:

答案 0 :(得分:5)

您的参数名为page,但您提供了id路由值。将操作方法​​中的page参数重命名为id,它应该可以正常工作。

答案 1 :(得分:2)

迈克尔回答了你的第一个问题。关于第二个问题,您可以使用第三方标记帮助程序,如pioneer-pagination

或者为下面的视图编写自己的分页逻辑实现(主要基于official documentation),不是完美的分页实现,但仍在工作:

页面模型:

public class PageViewModel
{
    public int PageNumber { get; }
    public int TotalPages { get; }

    public PageViewModel(int count, int pageNumber, int pageSize)
    {
        PageNumber = pageNumber;
        TotalPages = (int)Math.Ceiling(count / (double)pageSize);
    }

    public bool HasPreviousPage => (PageNumber > 1);

    public bool HasNextPage => (PageNumber < TotalPages);
}

代码帮助程序:

public class PagerTagHelper : TagHelper
{
    private IUrlHelperFactory urlHelperFactory;
    public PagerTagHelper(IUrlHelperFactory helperFactory)
    {
        urlHelperFactory = helperFactory;
    }
    [ViewContext]
    [HtmlAttributeNotBound]
    public ViewContext ViewContext { get; set; }
    public PageViewModel PageModel { get; set; }
    public string PageAction { get; set; }
    public string PageController { get; set; }

    public override void Process(TagHelperContext context, TagHelperOutput output)
    {
        IUrlHelper urlHelper = urlHelperFactory.GetUrlHelper(ViewContext);
        output.TagName = "div";

        // we put our links in list
        TagBuilder tag = new TagBuilder("ul");
        tag.AddCssClass("pagination");

        //show link for 1st page
        if (PageModel.PageNumber>2)
        {
              TagBuilder fstItem = CreateTag(1, urlHelper);
              tag.InnerHtml.AppendHtml(fstItem);
        }


        // create 3 links to current, next and previous page.
        TagBuilder currentItem = CreateTag(PageModel.PageNumber, urlHelper);

        // link to previous page if NOT 1st page
        if (PageModel.HasPreviousPage)
        {
            TagBuilder prevItem = CreateTag(PageModel.PageNumber - 1, urlHelper);
            tag.InnerHtml.AppendHtml(prevItem);
        }

        tag.InnerHtml.AppendHtml(currentItem);
        // link to next page, if NOT last page
        if (PageModel.HasNextPage)
        {
            TagBuilder nextItem = CreateTag(PageModel.PageNumber + 1, urlHelper);
            tag.InnerHtml.AppendHtml(nextItem);
        }


        //show code for last page
        if (PageModel.TotalPages > 4 && PageModel.PageNumber!=PageModel.TotalPages-1 && PageModel.HasNextPage)
        {
            TagBuilder lstItem = CreateTag(PageModel.TotalPages, urlHelper);
            tag.InnerHtml.AppendHtml(lstItem);
        }

        output.Content.AppendHtml(tag);
    }

    TagBuilder CreateTag(int pageNumber, IUrlHelper urlHelper)
    {
        TagBuilder item = new TagBuilder("li");
        TagBuilder link = new TagBuilder("a");
        if (pageNumber == this.PageModel.PageNumber)
        {
            item.AddCssClass("active");
        }
        else
        {
            link.Attributes["href"] = urlHelper.Action(PageAction, PageController, new { page = pageNumber });
        }
        link.InnerHtml.Append(pageNumber.ToString());
        item.InnerHtml.AppendHtml(link);
        return item;
    }
}

并在View中使用它(不要忘记在_ViewImports.cshtml中导入tag-helper ):

<pager page-model="@Model.PageViewModel" page-action="Index" page-controller="Home"></pager>

控制器的代码:

public async Task<IActionResult> Index(int page=1)
{
    int pageSize = 10;
    var count = await _context.Agent.CountAsync();
    var items = await _context.Agent.Skip((page - 1) * pageSize).Take(pageSize).ToListAsync();

    PageViewModel pageVm= new PageViewModel(count, page, pageSize);
    IndexViewModel vm= new IndexViewModel
    {
        PageViewModel = pageVm,
        Agents =items // need to create table in view from Agent properties
    };
    return View(vm);
}

IndexViewModel的代码:

public class IndexViewModel
{
    public IEnumerable<Agent> Agents { get; set; }
    public PageViewModel PageViewModel { get; set; }
}

<强>更新 如果您想在视图中显示所有PageLinks,您可以在Tag Helper Process方法中使用for循环,如下所示:

 public override void Process(TagHelperContext context, TagHelperOutput output)
 {
     IUrlHelper urlHelper = urlHelperFactory.GetUrlHelper(ViewContext);
     output.TagName = "div";

     // we put our links in list
     TagBuilder tag = new TagBuilder("ul");
     tag.AddCssClass("pagination");

     for (int i = 1; i <= PageModel.TotalPages; i++)
     {
         TagBuilder linkItem = CreateTag(i, urlHelper);
         tag.InnerHtml.AppendHtml(linkItem);
     }

     output.Content.AppendHtml(tag);
 }

更新2

为了使用这种方法,不要忘记将索引页的模型更改为IndexViewModel并在_ViewImports.cshtml中注册标记帮助程序。我的工作视图(简化)看起来像这样。

@* Using and tag helper imported in _ViewImports.cshtml *@
@model IndexViewModel

@{
    ViewData["Title"] = "Home";
}

<div>
    <table class="table">
        <tr><th>Name</th><th>Age</th></tr>
        @foreach (var a in Model.Agents)
        {
            <tr><td>@a.Name</td><td>@a.Age</td></tr>
        }
    </table>

</div>

<pager page-model="@Model.PageViewModel" page-action="Index" page-controller="Home"></pager>

更新3

  1. 如果您像我上面所写的那样使用IndexViewModel,但不像我的示例那样使用foreach,则应将@Html.DisplayNameFor(model => model.Name)更改为@Html.DisplayNameFor(model => model.Agents.Name)
  2. @addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers仅导入内置的ASP.NET Core标记帮助程序。要导入自定义代码,您应该使用@addTagHelper *, YourAssemblyName,其中YourAssemblyName是您项目的名称(例如,代理商代理商),有关详细信息,请参阅A minimal Tag Helper section in documentation