Question

我想创建有关电影的详细信息页面，但出现此错误，有点卡住了。我收到无法转换的类型错误。我确实知道该错误，但是我不知道如何解决它。

这是PAP实体是数据库实例的索引：

String address = addresses.get(0).getSubLocality();
String cityName = addresses.get(0).getLocality();
String stateName = addresses.get(0).getAdminArea();

这是我现在的详细信息类：

public class MoviesController : Controller
{

    PAPEntities db = new PAPEntities();


    public ActionResult Index()
    {

        MovieViewModel[] movies = db.MoviesData.Select(movie => new MovieViewModel
        {
            MovieID = movie.MovieID,
            MovieName = movie.MovieName,
            MovieDescription = movie.MovieDescription,
            MovieCategory = movie.MovieCategory,
            MovieYear = movie.MovieYear
        }).ToArray();

        return View(movies);

    }

我不断在“ db.MoviesData.Find（Id）;”上收到错误消息

这是MovieViewModel代码：

public ActionResult Details(int Id = 1)
    {
        MovieViewModel MovieVM = db.MoviesData.Find(Id);
        return View(MovieVM);
    }

这是剃须刀页面：

public class MovieViewModel
{
    public int MovieID { get; set; }
    public string MovieName { get; set; }
    public string MovieDescription { get; set; }
    public string MovieCategory { get; set; }
    public string MovieYear { get; set; }
}

@model WebApplication3.Models.MovieViewModel[]


@{
ViewBag.Title = "Index";
Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>Movies</h2>

<p>
@Html.ActionLink("Create New", "Create")

这是错误：

无法将类型'WebApplication3.Models.MoviesData'隐式转换为 'WebApplication3.Models.MovieViewModel'

MoviesData是数据库的表

Answer 1

您应该将数据库（MoviesData）模型映射到业务模型（MovieViewModel）

   public ActionResult Details(int Id = 1)
    {
        MoviesData movie = db.MoviesData.Find(Id);
        MovieViewModel MovieVM = new MovieViewModel();
        MovieVM.MovieID = movie.MovieID;
        MovieVM.MovieName = movie.MovieName;
        MovieVM.MovieDescription = movie.MovieDescription;
        MovieVM.MovieCategory = movie.MovieCategory;
        MovieVM.MovieYear = movie.MovieYear;

        return View(MovieVM);
    }

Answer 2

在您的dput(head(plotData,20)) structure(list(Date = structure(1:20, .Label = c("2001-12-03", "2001-12-04", "2001-12-05", "2001-12-06", "2001-12-07", "2001-12-10", "2001-12-11", "2001-12-12", "2001-12-13", "2001-12-14", "2001-12-17", "2001-12-18", "2001-12-19", "2001-12-20", "2001-12-21", "2001-12-24", "2001-12-25", "2001-12-26", "2001-12-27", "2001-12-28", "2001-12-31", "2002-01-01", "2002-01-02", "2002-01-03", "2002-01-04", "2002-01-07", "2019-05-22", "2019-05-23"), class = "factor"), Arima = c(-0.0134052258713131, -0.00542641764174324, 0.0128513670753771, 0.0282761455973665, 0.0179931884968989, 0.0281714817318116, 0.0435962602538011, 0.0462004298658309, 0.0194592964361352, 0.0248069155406948, 0.032807001046888, 0.0381120657516546, 0.0381120657516546, 0.030090589527961, -0.0146168717909267, -0.00630652663076437, -0.00630652663076437, -0.00630652663076437, 0.0100429785563596, 0.0100429785563596), BuyHold = c(-0.0134052258713131, -0.00542641764174324, 0.0128513670753771, 0.0282761455973665, 0.0384544388322794, 0.0281714817318116, 0.0125050470584384, 0.0151092166704679, -0.0116319167592278, -0.0170082867113405, -0.0090082012051471, -0.00370313650038065, -0.00370313650038065, -0.0117246127240743, -0.056432074042962, -0.0481217288827996, -0.0481217288827996, -0.0481217288827996, -0.0317722236956757, -0.0317722236956757)), row.names = c(NA, 20L), class = "data.frame")方法中，ActionResult Details返回类型为db.MoviesData.Find(Id)但变量类型为WebApplication3.Models.MoviesData的对象。这就是为什么您要例外。

您需要手动投射。因此，您可以这样编写代码，

MovieViewModel

如何解决无法转换类型错误？

2 个答案: