Get object out of List< Tuple < object1, object2 > > and store in ViewModel

问题

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Goal: 
Presentation of books with related inventorydetails on homepage 
such as Book.Title, InventoryDetail.Quantity etc. 
(Join|Book.BookId <=< InventoryDetail.BookId)

Problem 1: How to join

Problem 2: How to use a tuple (list of tuples)

Problem 3: How to store the separated objects (from the list of tuples) into a Strongly Typed ViewModel

Answer 1: An possible approach using Mike Brind's Guidance

Answer 2: Problem 1 and 2 tackled !!

Answer 3: Problem 3 tackled !!

Have fun with it. I'm happy to share!!!

public ActionResult Index()
{     
 // Return a list of tuples {(WebshopDB.Models.Book, WebshopDB.Models.InventoryDetail)}
 // Each tuple containing two items: 
 // > Item1 {WebshopDB.Models.Book}
 // > Item2 {WebshopDB.Models.InventoryDetail}
 var tuple_booksinventorydetails = ListOfTuples_BookInventoryDetail(5);

 // BEGIN UNDER CONSTRUCTION Setting up ViewModel
 // See below the code for the ViewModel
  var viewmodel = new HomeIndexViewModel()
  {
   // Problem // Book = tuple_books.Contains(Book).??,
   // Problem // InventoryDetail = tuple_books.Contains(InventoryDetail).??
  };
 // END

  return View(  .....  );
}

private List<Tuple<Book, InventoryDetail>> ListOfTuples_BookInventoryDetail(int count)
{
  var list_of_tuples = new List<Tuple<Book, InventoryDetail>>(); 

  var showbooks = webshopDB.Books
     .Join(webshopDB.InventoryDetails, b => b.BookId, i => i.BookId, (b, i) => new { b = b, i = i })
     .Where(o => (o.b.ShowInWebshop == true))
     .Where(o => o.b.BookThumbUrl.Contains(".jpg"))
     .Take(count);

  foreach (var item in showbooks)
  {
    list_of_tuples.Add( Tuple.Create<Book, InventoryDetail>( (item.b), (item.i) ) );
  }
  return list_of_tuples;
}

回答1:

As promised! I did reach my goal!!!

<%-- Index.apsx --%>
<%@ Page Title=" <Domain> " Language="C#" MasterPageFile="~/Views/Shared/Store.Master"
    Inherits="System.Web.Mvc.ViewPage<HomeTupleIndexViewModel>" %>

<%-- Mandatory 'Import' --%>
<%@ Import Namespace="<Domain>.ViewModels" %>   

<asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
  <%--....--%>
</asp:Content>

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
  <%-- Exerecise Tuple --%>
  <% Html.RenderPartial("BookPartial", Model.Book); %>
  <% Html.RenderPartial("InventoryDetailPartial", Model.InventoryDetail); %>
</asp:Content>


<%-- BookPartial.ascx --%>
<%-- Currently this ViewPartial is a Strongly Typed ViewPartial %> --%>
<%@ Control Language="C#" 
    Inherits="System.Web.Mvc.ViewUserControl<IEnumerable< <Domain> .Models.Book>>" %>
<%@ Import Namespace=" <Domain> .Helpers" %>
<%-- Strongly Typed ViewPages--%>
<ul id="...">
  <% foreach (var item in Model) {%>  
<li>
  <div id="...">
    <p>
      <a href="<%: Url.Action("Details", "Store", new { id = item.BookId }) %>">
        <div id="...">
          <h2>
            <span><%: item.Genre %></span>
          </h2>
        </div>
        <div id="...">
          <img alt="<%: item.Title %>" src="<%: item.BookThumbUrl %>" />
        </div>
        <div id="...">  
          <span><%: item.Title %></span>
        </div>
      </a> 
    </p>
  </div>
    </li> 
  <% } %>
</ul>


<%-- InventoryDetailPartial.ascx --%>
<%@ Control Language="C#" 
    Inherits="System.Web.Mvc.ViewUserControl<IEnumerable< <Domain> .Models.InventoryDetail>>" %>
<%@ Import Namespace=" <Domain> .Helpers" %>
<%-- Strongly Typed ViewPages--%>
<ul id="...">
  <% foreach (var item in Model) {%>  
<li>
  <div id="...">
    <p> 
      <div id="...">  
        <span>
          <% if (item.Quantity == 1) 
                 { %> 
             <%: Server.HtmlDecode(Html.Translation("Stock_Amount"))%>&nbsp;<%: item.Quantity %>&nbsp;<%: Server.HtmlDecode(Html.Translation("Copy"))%>
          <% } 
                 else if (item.Quantity > 1) %> 
              <% { %>
             <%: Server.HtmlDecode(Html.Translation("Stock_Amount"))%>&nbsp;<%: item.Quantity %>&nbsp;<%: Server.HtmlDecode(Html.Translation("Copies"))%>
          <% } 
                 else 
                 { %>
             <%: Server.HtmlDecode(Html.Translation("Sold_Out"))%>
          <% } %>
        </span>
      </div>
    </p>
  </div>
</li>
  <% } %>
</ul>

So, finally I ended up with an Index.aspx calling two separate Partial Views (I prefer to speak about 'controls' instead of 'partials', however, this is just a matter of personal taste).

Compared to Mike Brind's guide (mentioned in my first answer) by using this tuple 'path' guide you'll finally have more 'freedom' to do as you like on the index page. The 'related' objects (!! the 'join' remember !!) are nicely separated in the presentation layer, however still strongly related!

回答2:

Answer ( Solution for my own posted question! )

  // Instantiate new lists needed to add the to be separated objects of the tuple
  List<Book> T1 = new List<Book>();
  List<InventoryDetail> T2 = new List<InventoryDetail>();

  // Iterate through the tuple and add each 'item' of each tuple into the new instantiated lists
  for (int i = 0; i < tuple_booksinventorydetails.Count; i++)
  {
    var tuple = tuple_booksinventorydetails[i];
    // Item1
    T1.Add(tuple.Item1);
    // Item2
    T2.Add(tuple.Item2);
  }

  // Instantiate a new viewmodel to store the separated lists

  // ==HomeTupleIndexViewMode Class==
  //using System;
  //using System.Collections.Generic;
  //using <Domain>.Models;
  //namespace <Domain>.ViewModels
  //{
  //  public class HomeTupleIndexViewModel
  //  {
  //    public List<Book> Book { get; set; }
  //    public List<InventoryDetail> InventoryDetail { get; set; }
  //  }
  //}
  // ==

  HomeTupleIndexViewModel tupleviewdata = new HomeTupleIndexViewModel() 
  { 
   Book = T1,
   InventoryDetail = T2
  };
  return View(tupleviewdata);

来源：https://stackoverflow.com/questions/4189730/get-object-out-of-list-tuple-object1-object2-and-store-in-viewmodel