Question

我已经使用Code First方法在两个实体之间设置了多对多关系。不幸的是，我无法创建下拉列表以选择不同的值并将其添加到对象中。

您能在我的代码中指出错误或缺少的部分吗？

public class Vacancy : IAuditable
{
public Vacancy(){}

/// <summary>
/// General properties
/// </summary>
public int Id { get; set; }

{removing code for simplicity}

/// <summary>
/// A vacancy could have many HBO-I Skills.
/// The ICollection contains a list of HBO-I Skills which consist the HBO-I Skills for the particular vacancy.
/// </summary>
public virtual ICollection<VacancyHBOISkill> VacancyHBOISkills { get; set; }

 }

public class HBOISkill : IAuditable
{
public HBOISkill(){}

/// <summary>
/// General properties
/// </summary>
public int Id { get; set; }

{removing code for simplicity}

/// <summary>
/// Many vacancies provides 1 or more HBO-I Skills.
/// </summary>
public virtual ICollection<VacancyHBOISkill> VacancyHBOISkills { get; set;             }     
}

空缺与HBOISkill之间的交集表

     public class VacancyHBOISkill
     {
        public int VacancyId { get; set; }
        public Vacancy Vacancy { get; set; }

        public int HBOISkillId { get; set; }
        public HBOISkill HBOISkill { get; set; }
     }

VacancyHBOISkill类的配置

   public void Configure(EntityTypeBuilder<VacancyHBOISkill> entityBuilder)
    {
        entityBuilder
        .HasKey(vh => new { vh.VacancyId, vh.HBOISkillId });
    }

DbContext类

{removing code for simplicity}

    /// <summary>
    /// Defining the database tables within our application
    /// </summary    
    public DbSet<Vacancy> Vacancy { get; set; }
    public DbSet<HBOISkill> HBOISkill { get; set; }
    public DbSet<VacancyHBOISkill> VacancyHBOISkill { get; set; }

     // Adding the Shadow Properties to database schemas when we creating the DbModel
    protected override void OnModelCreating(ModelBuilder builder)
    {
        {removing code for simplicity}

        /// <summary>
        /// Loading the configuration files for the entities
        /// </summary
        builder.ApplyConfiguration(new VacancyConfiguration());
        builder.ApplyConfiguration(new HBOISkillConfiguration());
        builder.ApplyConfiguration(new VacancyHBOISkillConfiguration());
    }

我的剃刀页面代码：

    public IActionResult OnGet()
    {

    ViewData["TypeId"] = new SelectList(_context.VacancyType, "Id", "Name");
    ViewData["CategoryId"] = new SelectList(_context.Category, "Id", "Desc");
    //ViewData["VacancyHBOSKillId"] = new SelectList(_context.HBOISkill, "Id", "Name");

    return Page();
    }

    [BindProperty]
    public Vacancy Vacancy { get; set; }

    public IEnumerable<HBOISkill> HBOISkillList { get; set; }
    public IEnumerable<SelectListItem> GetHBOISkillSelectList()
    {
        return HBOISkillList
            .Select((hs, i) => new SelectListItem
            {
                Text = hs.Name.ToString(),
                Value = hs.Id.ToString()
                //Selected = hs.Id == Vacancy.VacancyHBOISkills.Add(Vacancy.Id, hs.Id)
            });
    }

下面您将找到我的数据库（表）的图片（屏幕快照）。

Database tables
Vacancy class
HBOISkill
VacancyHBOISkill

先谢谢了，
真诚的
Halil

P.S。我将类名从复数更改为单数，这些更改在（旧的）屏幕截图中不可见。

使用Code First方法和FluentAPI

0 个答案: