c# - 无法从 SelectList Razor Pages 中获取选定的值

问题描述

我正在使用Razor Pages. 我有两个模型：Movie * - 1 Genre。我想要的是，当我导航到流派页面并选择特定流派时，我想显示与此流派关联的所有电影的列表，并且我希望能够从流派中选择并导航到电影。

我遇到的问题是 Razor Pages 的SelectList没有从列表中绑定选定的参考值（即电影的对象），但是当我有IDs电影时，我正确地获得了选定的值。

这是我的代码：

详细信息.cshtml

<div>
<h4>Genre</h4>
<hr />
<form method="post">
    <dl class="row">
        <dt class="col-sm-2">
            @Html.DisplayNameFor(model => model.Genre.GenreTitle)
        </dt>
        <dd class="col-sm-10">
            @Html.DisplayFor(model => model.Genre.GenreTitle)
        </dd>
    </dl>
    <div class="form-group" style="width: 250px;">
        <label asp-for="MoviesSL" class="control-label"></label>
        <select asp-for="SelectedMovie" class="form-control"
                asp-items="Model.MoviesSL">
        </select>
    </div>
    <span asp-validation-for="SelectedMovie.ID" class="text-danger"></span>
    <div>
        <input type="submit" value="Navigate" class="btn btn-info" />
    </div>
</form>

详细信息.cshtml.cs

    public Genre Genre { get; set; }
    [Display(Name = "Movies list")]
    public SelectList MoviesSL { get; set; }
    private Movie selectedMovie;
    [BindProperty]
    public Movie SelectedMovie 
    {
        get => selectedMovie;
        set
        {
            selectedMovie = value;
            //int g = 0;
        }
    }

    public async Task<IActionResult> OnGetAsync(int? id)
    {
        if (id == null)
        {
            return NotFound();
        }

        Genre = await _context.Genre.Include(m => m.Movies).FirstOrDefaultAsync(m => m.GenreId == id);
        MoviesSL = new SelectList(Genre.Movies);

        //int g = 0;

        if (Genre == null)
        {
            return NotFound();
        }
        return Page();
    }

    public void OnPost()
    {
        var k = SelectedMovie;

        //int g = 0;
    }

电影.cs

public class Movie
    {
        [Key]
        public int ID { get; set; }

        [Required]
        [StringLength(60, MinimumLength = 3)]
        public string Title { get; set; }

        [DataType(DataType.Date)]
        [Display(Name = "Release Date")]
        [DisplayFormat(DataFormatString = "{0:dd-MM-yyyy}", ApplyFormatInEditMode = true)]
        public DateTime ReleaseDate { get; set; }

        [Range(1, 300)]
        [DataType(DataType.Currency)]
        [Column(TypeName = "decimal(18,2)")]
        public decimal Price { get; set; }

        [Required]
        [StringLength(5)]
        [RegularExpression(@"^[A-Z]+[a-zA-Z0-9""'\s-]*$")]
        public string Rating { get; set; }

        public int GenreId { get; set; }
        public Genre Genre { get; set; }

        public override string ToString()
        {
            return Title;
        }
    }

流派.cs

public class Genre
{
    public Genre()
    {
        Movies = new List<Movie>();
    }

    [Key]
    public int GenreId { get; set; }
    [Required]
    [StringLength(30, MinimumLength = 5)]
    [Display(Name = "Genre Title")]
    [RegularExpression(@"^[A-Z]+[a-zA-Z]*$")]
    public string GenreTitle { get; set; }

    [Display(Name = "Number of movies")]
    public ICollection<Movie> Movies { get; set; }

    public override string ToString()
    {
        return GenreTitle;
    }
}

当我从列表中选择一部电影并尝试通过 post 方法“导航”时，我得到一个空的Movie对象。

但是，当我有SelectList of IDsinsteadMovies时，它可以正常工作：

标签： c#asp.net-core.net-corerazor-pagesselectlist

c# - 无法从 SelectList Razor Pages 中获取选定的值

问题描述

解决方案

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