时间戳

首页 > 解决方案 > 提交表单时无法获取外键值

c# - 提交表单时无法获取外键值

问题描述

我目前在我的ASP.NET Core项目中工作。我创建了一些已映射到数据库表的类。

差事类：

public class Errand : IDbEntity
{
    public int Id { get; set; }
    public int PANumber { get; set; }
    public string Description { get; set; }
    public string Issuer { get; set; }
    public string Stakeholders { get; set; }
    public string Background { get; set; }
    public string DescriptionOfMission { get; set; }
    public string AcceptanceCriteria { get; set; }
    public string TestObject { get; set; }
    public DateTime AvailableFrom { get; set; }
    public DateTime TestStart { get; set; }
    public DateTime TestDelivery { get; set; }
    public DateTime Created { get; set; }
    public DateTime Updated { get; set; }

    public int CoreId { get; set; }
    public virtual Core Core { get; set; }

    public int MachineTypeId { get; set; }
    public virtual MachineType MachineType { get; set; }

    public int ProjectNrId { get; set; }
    public virtual ProjectNumber ProjectNr { get; set; }

    public int TestTypeId { get; set; }
    public virtual Group TestType { get; set; }

    public virtual DBErrandStatus status { get; set; }
}

其他类看起来彼此相同。这是Core的类：

public class Core : IDbEntity
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTime Created { get; set; }
    public DateTime Updated { get; set; }

    public virtual ICollection<Errand> Errands { get; set; }
}

我已经迁移到数据库，一切正常，并且 Errand 表包含Core, Group, MachineType & ProjectNumber.

现在到我的问题。我正在尝试创建 AErrand并在用户将为差事选择值的视图中为外键创建下拉列表。这是代码：

 <form method="post" asp-controller="Home" asp-action="ExecuteCreateErrand">
    <div class="row">
        <div class="col-md-2">
            <label>PA number:</label>
            <input asp-for="@Model.errand.PANumber" class="form-input" type="text" />
        </div>
        <div class="col-md-4">
            <label>Title:</label>
            <input asp-for="@Model.errand.Description" class="form-input" placeholder="Title" type="text" />
        </div>
        <div class="col-md-2">
            <label>Core:</label>
            <select asp-for="@Model.errand.Core" class="form-input">
                @foreach(var core in Model.Core)
                {
                    <option>@core.Name</option>
                }
            </select>
        </div>
        <div class="col-md-4">
            <label>Project Nr:</label>
            <select asp-for="@Model.errand.ProjectNr" class="form-input">
                @foreach(var projNr in Model.ProjectNumber)
                {
                    <option>@projNr.Name</option>
                }
            </select>
        </div>
    </div>
    <div class="row">
        <div class="col-md-2">
            <label>Machine type:</label>
            <select asp-for="@Model.errand.MachineType" class="form-input">
                @foreach (var MT in Model.MachineType)
                {
                    <option>@MT.Name</option>
                }
            </select>
        </div>
        <div class="col-md-4">
            <label>Issuer:</label>
            <input asp-for="@Model.errand.Issuer" class="form-input" value="@Model.User.Username" type="text" readonly />
        </div>
        <div class="col-md-2">
            <label>Test type</label>
            <select asp-for="@Model.errand.TestType" class="form-input">
                @foreach (var TestType in Model.TestType)
                {
                    <option>@TestType.Name</option>
                }
            </select>
        </div>
        <div class="col-md-4">
            <label>Stakeholders</label>
            <input class="form-input" asp-for="@Model.errand.Stakeholders" placeholder="Stakeholders" type="text" />
        </div>
    </div>
    <div class="row">
        <div id="sandbox-container" class=" span5 col-md-4">
            <label>Testobject avalible from:</label>
            <input asp-for="@Model.errand.AvailableFrom" class="form-input" type="text" value="@DateTime.Now.ToString("yyyy/MM/dd")" />
        </div>

        <div id="sandbox-container" class=" span5 col-md-4">
            <label>Desired start of test:</label>
            <input asp-for="@Model.errand.TestStart" class="form-input" type="text" value="@DateTime.Now.ToString("yyyy/MM/dd")" />
        </div>

        <div id="sandbox-container" class=" span5 col-md-4">
            <label>Desired end of test:</label>
            <input asp-for="@Model.errand.TestDelivery" class="form-input" type="text" value="@DateTime.Now.ToString("yyyy/MM/dd")" />
        </div>
    </div>
    <div class="row">
        <div class="col-md-10"></div>
        <div class="col-md-2">
            <button type="submit" class="btn btn-lg btn-block mt-4 vBtn">Create Errand</button>
        </div>
    </div>
</form>

但是，当我后来在提交表单后运行的操作上设置断点时，我得到Errand.Core = null了Errand.CoreId = 0

这是该操作的代码：

public IActionResult ExecuteCreateErrand([FromForm] Errand errand)
    {
        var SQL = new SQLErrandStorage();
        var handler = new ErrandHandler(SQL);
        handler.Create(errand);

        return RedirectToAction("RenderAllErrandsView", "Home");
    }

[FromForm] Errand errand返回这个

核心 = null 和 CoreId = 0

Action 调用此方法：

public void Create(Errand errand)
{
     errandStorage.CreateErrand(errand);
}

它又调用这个创建差事的方法：

public void CreateErrand(Errand errand)
    {
        using (var db = new PADBContext())
        {
            db.Errand.Add(errand);
            db.SaveChanges();
        }
    }

我的问题是如何使外键附加在提交的表单中。如何将值更改为Core = null and CoreId = 0我在下拉列表中选择的值？

我希望这能很好地解释我的问题。我真的很感激一些帮助或一些反馈。提前致谢！

标签： c#sql-serverentity-frameworkasp.net-core

解决方案

问题似乎是标签助手中asp-for值的错误绑定。指定选择元素的模型属性名称，而不是模型。selectSelect Tag Helper asp-for

如果你想得到Errand.CoreId，你可以设置如下asp-for的选择标签助手：

<label>Core:</label>
<select asp-for="@Model.errand.CoreId" class="form-input">
      @foreach (var core in Model.Core)
       {
         <option value="@core.Id">@core.Name</option>
       }
 </select>

如果你想得到Errand.Core，你可以设置选择标签助手的 asp-for，如下所示：

<label>Core:</label>
<select asp-for="@Model.errand.Core.Id" class="form-input">
      @foreach (var core in Model.Core)
       {
         <option value="@core.Id">@core.Name</option>
       }
 </select>

推荐阅读