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我有一个 Inventory 类，它不仅包含它自己的字段，还包含几个对其他类的引用 ID。

public class Inventory {

  public int Id { get; set; }

  public string RtNum { get; set; }

  public string AcntNum { get; set; }

  public string CardNum { get; set; }

  public string Num { get; set; }

  [Range(1,3)]
  public int Type { get; set; }

  public int CompanyId { get; set; }

  public int BranchId { get; set; }

  public int PersonId { get; set; }   }

在我的操作中，我从其他类中生成了几个相关字段的 IEnumerable 列表。我还有几个要传递给视图的非列表值。我知道如何创建 ViewModel 以将所有内容传递给 webgrid，但无法遍历列表。我也知道如何将索引自动映射到一个列表，请参阅如何在 MVC WebGrid 中显示行号。您将如何将两者结合起来，以便可以使用索引来遍历多个列表？

更新#1（更多细节）

public class Company {
  public int Id { get; set; } 
  public string Name { get; set; }   }

public class Branch {
  public int Id { get; set; } 
  public string Name { get; set; }   }

public class Person  {
  public int Id { get; set; } 
  public string Name { get; set; }   }

public class MyViewModel  {
  public int PageNumber { get; set; }
  public int TotalRows { get; set; }
  public int PageSize { get; set; }
  public IEnumerable<Inventory> Inventories { get; set; }
  public int Index { get; set; }
  public IEnumerable<string> CmpNm { get; set; }
  public IEnumerable<string> BrnNm { get; set; }
  public IEnumerable<string> PrnNm { get; set; }        }

控制器

public class InventoryController : Controller
{  // I have a paged gird who’s code is not relevant to this discussion but a pagenumber,
   //  pagesize and totalrows will be generated
   private ProjectContext _db = new ProjectContext();

   public ActionResult Index()  {
     IEnumerable<Inventory> inventories = _db.Inventories;
     List<string> cmpNm = new List<string>; List<string> brnNm = new List<string>; List<string>     prnNm = new List<string>;
     foreach (var item in inventories) { string x1 = ""; 
     Company cmps = _db. Company.SingleOrDefault(i => i.Id == item.CompanyId); if (cmps!= null)
      { x1 = cmps.Name; } cmpNm.Add(x1); x1 = "";
     Branch brns = _db. Branch.SingleOrDefault(i => i.Id == item. Branch Id); if (brns!= null) { x1 = brns.Name; } brnNm.Add(x1); x1 = "";
     Person pers = _db.Persons.SingleOrDefault(i => i.Id == item. PersonId);
      if (pers!= null) { x1 = pers.Name; } prnNm.Add(x1); 

     // the MyViewModel now needs to populated with all its properties and generate an index
     // something along the line of 
     new MyViewModel { PageNumber= pagenumber, PageSize= pagesize,  TotalRows=Totalrows, Inventories = inventories;  CmpNm=cmpNm, BrnNm=brnNm, PrnNm=prnNm}

查看（如何创建索引是问题）

@model.Project.ViewModels.MyViewModel
@{ var grid = new WebGrid(Model.Inventories, Model.TotalRows, rowsPerPage: Model.PageSize); }
@grid.GetHtml( columns: grid.Columns( 
    Grid.Column(“PrnNm”, header: "Person", format: @Model.PrnNm.ElementAt(Index))
    Grid.Column(“BrnNm”, header: "Branch", format: @Model.BrnNm.ElementAt(Index))
    Grid.Column(“CmpNm”, header: "Company", format: @Model.CmpNm.ElementAt(Index))
    grid.Column("RtNum", header: "Route"), 
    grid.Column("AcntNum", header: "Account"), 
    grid.Column("CardNum", header: "Card")
    …      )    )

网格应该是什么样子是不言而喻的。

4

1 回答 1

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目前还不清楚你的目标是什么。但无论它是什么，我都建议您定义一个真实的视图模型，以反映您的视图要求并仅包含您有兴趣在此网格中看到的信息：

public class InventoryViewModel
{
    public int Id { get; set; }
    public string PersonName { get; set; }
    public string BranchName { get; set; }
    public string CompanyName { get; set; }
    public string RouteNumber { get; set; }
    public string AccountNumber { get; set; }
    public string CardNumber { get; set; }
}

现在您可以拥有主视图模型：

public class MyViewModel
{
    public int PageNumber { get; set; }
    public int TotalRows { get; set; }
    public IEnumerable<InventoryViewModel> Inventories { get; set; }
}

好的，现在视图很明显：

@model MyViewModel

@{ 
    var grid = new WebGrid(
        Model.Inventories, 
        rowsPerPage: Model.PageSize
    ); 
}

@grid.GetHtml( 
    columns: grid.Columns( 
        grid.Column("Id", header: "Inventory id"),
        grid.Column("PersonName", header: "Person"),
        grid.Column("BranchName", header: "Branch"),
        grid.Column("CompanyName", header: "Company"),
        grid.Column("RouteNumber", header: "Route"), 
        grid.Column("AccountNumber", header: "Account"), 
        grid.Column("CardNumber", header: "Card")
    )    
)

现在剩下的就是在你的控制器中构建这个视图模型。由于我不知道您要在这里实现什么，无论您需要在这些列上进行内连接还是左外连接，我将在这里以左外连接为例：

public ActionResult Index()
{
    var inventories = 
        from inventory in _db.Inventories
        join person in _db.Persons on inventory.PersonId equals person.Id into outerPerson
        join company in _db.Companies on inventory.CompanyId equals company.Id into outerCompany
        join branch in _db.Branch on inventory.BranchId equals branch.Id into outerBranch
        from p in outerPerson.DefaultIfEmpty()
        from c in outerCompany.DefaultIfEmpty()
        from b in outerBranch.DefaultIfEmpty()
        select new InventoryViewModel
        { 
            PersonName = (p == null) ? string.Empty : p.Name,
            CompanyName = (c == null) ? string.Empty : c.Name,
            BranchName = (b == null) ? string.Empty : b.Name,
            Id = inventory.Id,
            AccountNumber = inventory.AcntNum,
            CardNumber = inventory.CardNum,
            RouteNumber = inventory.RtNum
        };


    var model = new MyViewModel
    {
        PageSize = 5,
        // TODO: paging
        Inventories = inventories.ToList()
    };

    return View(model);
}

差不多就是这样。当然，在这个例子中，我将把 Inventories 集合的分页留给你。.Skip()现在，.Take()您需要的记录数量应该是微不足道的。

As you can see ASP.NET MVC is extremely simple. You define a view model to reflect the exact requirements of what you need to show in the view and then populate this view model in the controller. Most people avoid view models because they fail to populate them, probably due to lack of knowledge of the underlying data access technology they are using. As you can see in this example the difficulty doesn't lie in ASP.NET MVC at all. It lies in the LINQ query. But LINQ has strictly nothing to do with MVC. It is something that should be learned apart from MVC. When you are doing MVC always think in terms of view models and what information you need to present to the user. Don't think in terms of what you have in your database or wherever this information should come from.

于 2012-10-16T07:24:02.717 回答