c# - 如何将外键从一个 View 传递到另一个 View ？

Question

我对 .NET 和 MVC 还很陌生，我正在尝试找出模型关系。
我有 2 个模型，用于预订研讨会。

namespace App.Models{
    public class PreBook{
        [Key]
        public int IdPreBook{get; set;}
        [DataType(DataType.Date)]
        public DateTime Date { get; set; }
        public string  Name { get; set; }
        public string Surname { get; set; }
        public string Adress { get; set; }
        public string Email { get; set; }
        public string PhoneNum { get; set; }
        [ForeignKey("Seminar")]
        public int IdSeminar { get; set; }
        public Seminar Seminar {get;set;}
    }
}

.

namespace App.Models{
    public class Seminar{
        [Key]
        public int IdSeminar {get; set;}
        public string Name {get;set;}
        public string Description {get;set;}
        [DataType(DataType.Date)]
        public DateTime Date{ get; set; }
        public bool Filled { get; set; }
        public List<Predbiljezba> Predbiljezbe {get; set;}
    }
}

我的索引 View 列出了所有未满/满的研讨会。
Index view

@model IQueryable<Seminar>

<div class="container p-3">
    <div class="row pt-4">
        <form asp-action="Index" method="get">
            <div class="form-actions no-color">
                <p>
                    <b>Search:</b> <input type="text" name="SearchString" value="@ViewData["CurrentFilter"]" />
                    <input type="submit" value="Search" class="btn btn-default" /> |
                    <a asp-action="Index">Back to Full List</a>
                </p>
            </div>
        </form>
    </div>
 @if(Model.Count() > 0){
    <table class="table table-bordered table-striped" style="width:100%">
        <thead>
            <tr>
                <th>
                    
                </th>
                <th>
                    Name
                </th>
                <th>
                    Description
                </th>
                <th>
                    Date
                </th>
            </tr>
        </thead>
        <tbody>
            @foreach (var item in Model)
            {
                if(!item.Filled){
                    <tr>
                    <td class="text-center">
                        <a asp-controller="PreBook" asp-route-Id="@item.IdSeminar" asp-action="PreBook">Choose</a>
                    </td>
                    <td width="40%">@item.Naziv</td>
                    <td width="20%">@item.Opis</td>
                    <td width="20%">@item.Datum</td>
                    <!----<td width="30%"></td>---->

                </tr>
                }
            }
        </tbody>
    </table>
}else{
    <p>No category exists.</p>
}

这是我单击“选择”时调用的 Prebook 操作，这是我需要帮助的地方。

public IActionResult PreBook(){
    ViewData["IdSeminara"] = new SelectList(_context.Seminars, "IdSeminar", "Naziv");
    return View();
}

这是后期操作:

[HttpPost]
[ValidateAntiForgeryToken]
public IActionResult PreBook(PreBook obj)
{
    if (ModelState.IsValid)
    {
        _context.PreBooks.Add(obj);
        _context.SaveChanges();
        return RedirectToAction("Index");
    }
    else
    {
        return View(obj);
    }
}

这是预定 View 。
PreBook View
及其代码:

@model PreBook


<form method="post" asp-action="PreBook">
    <div class="border p-3">
        <div asp-validation-summery="ModelOnly" class="text-danger"></div>
        <p></p>
        <h4>I want to display chosen seminar name here</h4>
        <div class="row">
            <div class="col-8">
                <div class="form-group row">
                    <div class="col-4">
                        <b>Name:</b>
                    </div>
                    <div class="col-8">
                        <input asp-for="Name" class="form-control" />
                        <span asp-validation-for="Name" class="text-danger"></span>
                    </div>
                </div>
                <div class="form-group row">
                    <div class="col-4">
                        <b>Surname:</b>
                    </div>
                    <div class="col-8">
                        <input asp-for="Surname" class="form-controll" />
                        <span asp-validation-for="Surname" class="text-danger"></span>
                    </div>
                </div>
                <div class="form-group row">
                    <div class="col-4">
                        <b>Adress:</b>
                    </div>
                    <div class="col-8">
                        <input asp-for="Adress" class="form-controll" />
                        <span asp-validation-for="Adress" class="text-danger"></span>
                    </div>
                </div>
                <div class="form-group row">
                    <div class="col-4">
                        <b>Email:</b>
                    </div>
                    <div class="col-8">
                        <input asp-for="Email" class="form-controll" />
                        <span asp-validation-for="Email" class="text-danger"></span>
                    </div>
                </div>
                <div class="form-group row">
                    <div class="col-4">
                        <b>Phonenumber:</b>
                    </div>
                    <div class="col-8">
                        <input asp-for="PhoneNum" class="form-controll" />
                        <span asp-validation-for="PhoneNum" class="text-danger"></span>
                    </div>
                </div>
                <div class="form-group row">
                    <input type="submit" value="Confirm" class="btn btn-primary" />
                </div>
            </div>
            <div class="col-4">
                @*Keep this empty*@
            </div>
        </div>
    </div>

那么，当我选择要预订的研讨会时，如何将其 key 发送到 PreBook View 并将其作为 PreBook 模型中的外键保存到 DB？ (我还想在 PreBook View 中显示选定的研讨会名称)。我一直在寻找这一整天，但没有找到任何明确的解释。
dotnet 和 ef 都是 5.0

Answer 1

试试这个，它应该工作

[Route("Prebook/Prebook/{id}")]
public IActionResult PreBook(int Id){
//Get name of seminar from id
string seminarName=_context.Seminars.Where(x=>x.Id==Id).FirstOrDefault().Name;
Seminar sem=new Seminar(){Name=seminarName,Id=Id);
Prebook pre=new Preebook(){Seminar=sem,IdSeminar=Id}
return View(pre);
}

在 View 中，您可以使用以下代码

               <div class="col-8">
                    <input type="hidden" value="IdSeminar" name="idSeminar"/>
                    <input asp-for="Seminar.Name" class="form-control" />
                    <span asp-validation-for="Seminar.Name" class="text-danger"> 
                    </span>
                </div>

还将异常处理应用于预订插入。

[HttpPost]
[ValidateAntiForgeryToken]
public IActionResult PreBook(PreBook obj)
 {
 if (ModelState.IsValid)
 {
      obj.Seminar=null;
  try{
    _context.PreBooks.Add(obj);
    _context.SaveChanges();
   }
catch(Exception ex)
 {
 Debug.Write(ex.Message);
 }
    return RedirectToAction("Index");
}
else
{
    return View(obj);
}
}