如何获得关联关系答案

【问题标题】：How to get a linked relationship如何获得关联关系
【发布时间】：2021-10-07 13:14:30
【问题描述】：

我有基础模型

public class Group
{
    public int Id { get; set; }
    public int GroupVag { get; set; }
    public ICollection<Vagon> Vagons { get; set; }
}

public class Vagon 
{
    public int Id { get; set; }
    public string Nom_Vag { get; set; }
    //[Required]
    public int NumberGroup { get; set; }
    [ForeignKey("Group")]
    public int? GroupId { get; set; }
    public Group Group { get; set; }
    public virtual ICollection<SPR4664> SPR4664s { get; set; }
}

我的视图模型

public class ViewModelAddVag
{
    public int Id { get; set; }
    [Display(Name = "Name vag")]
    [Required]
    [MaxLength(8, ErrorMessage = "incorrect")]
    public string Nom_Vag { get; set; }

    [Display(Name = "Group vag")]
    //[Required]
    public int NumberGroup { get; set; }
    [Display(Name = "TrainingType")]
    [UIHint("DropDownList")]
    public IEnumerable<SelectListItem> GroupDictionary { get; set; }
}

我想加入 View DropDownList table Group。我为它做了 ViewModel。但我不知道该怎么做？我想我应该在 ViewModel 使用属性 Get 中得到它

public IEnumerable<SelectListItem> GroupDictionary { get; set; }

【问题讨论】：

标签： c# model-view-controller asp.net-mvc-5

【解决方案1】：

我想得到什么：

查看

<div class="form-group">
        <div class="col-md-10">
            
                Grops <br />
                @Html.DropDownListFor(model => model.Id, ViewBag.Group as SelectList, null, new { @class = "btn btn-info dropdown-toggle" })
            
            <select name="TrainingTypeId" class="btn btn-light dropdown-toggle dropdown-toggle-split" aria-label="Default select example">
                @foreach (var item in ViewBag.Group)
                {
                    <option value="@item.Value">
                        @item.Text
                    </option>
                }
            </select>
            </div>
        </div>

控制器：

    [HttpGet]
    public ActionResult Create()
    {
        SelectList groupsList = new SelectList(db.groups, "Id", "GroupVag");
        ViewBag.Group = groupsList;
        return View();
    }

【讨论】：