在链接到现有对象的数据库中插入对象

本文关键字：对象 数据库 插入 链接 | 更新日期: 2023-09-27 18:00:46

我有一个名为"专业"的对象，我的专业有一个"技能"列表

当我试图为确定的专业插入一项新技能时，我遇到了一个问题

我试着在发布新对象的视图中这样做：

<div>
    @Html.ActionLink("Add Skill", "AddNewSkill", new { skill = Model, id = ViewBag.professionalId} ) 
</div>

控制器方法

        public ActionResult AddNewSkill(int professionalId)
        {
            ViewBag.professionalId = professionalId;
            return View();
        }
        [HttpPost]
        public ActionResult AddNewSkill(SkillModel skill, int professionalId)
        {
            professionalBusiness = new ProfessionalBusiness();
            var professional = professionalBusiness.GetById(professionalId);
            professional.Skills.Add(skill);
            if (ModelState.IsValid)
            {
                professionalBusiness.Update(professional);
                return RedirectToAction("Index");
            }
            return RedirectToAction("Edit", professionalId);
        }

但这更糟糕，因为我的URL只显示了一个参数

http://localhost:20995/Professional/AddNewSkill/1

当我尝试POST时，它会给我一个错误：

[ArgumentException: The parameters dictionary contains a null entry for parameter 'professionalId' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult AddNewSkill(Int32)' in 'TCCApplication.Controllers.ProfessionalController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
Nome do parâmetro: parameters]
   System.Web.Mvc.ActionDescriptor.ExtractParameterFromDictionary(ParameterInfo parameterInfo, IDictionary`2 parameters, MethodInfo methodInfo) +607955
   System.Web.Mvc.<>c__DisplayClass1.<Execute>b__0(ParameterInfo parameterInfo) +18
   System.Linq.WhereSelectArrayIterator`2.MoveNext() +66
   System.Linq.Buffer`1..ctor(IEnumerable`1 source) +216
   System.Linq.Enumerable.ToArray(IEnumerable`1 source) +77
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +135
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +27
   System.Web.Mvc.Async.<>c__DisplayClass42.<BeginInvokeSynchronousActionMethod>b__41() +28
   System.Web.Mvc.Async.<>c__DisplayClass8`1.<BeginSynchronous>b__7(IAsyncResult _) +10
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +48
   System.Web.Mvc.Async.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33() +57
   System.Web.Mvc.Async.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() +223
   System.Web.Mvc.Async.<>c__DisplayClass37.<BeginInvokeActionMethodWithFilters>b__36(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +48
   System.Web.Mvc.Async.<>c__DisplayClass2a.<BeginInvokeAction>b__20() +24
   System.Web.Mvc.Async.<>c__DisplayClass25.<BeginInvokeAction>b__22(IAsyncResult asyncResult) +102
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +43
   System.Web.Mvc.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult) +14
   System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +57
   System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +47
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
   System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult) +25
   System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +47
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9690164
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

在链接到现有对象的数据库中插入对象

您的参数名称在调用和控制器操作之间不匹配。

尝试将呼叫更改为：

@Html.ActionLink("Add Skill", "AddNewSkill", new { skill = Model, professionalId = ViewBag.professionalId} )

编辑：

使用@Html.ActionLink()将表单数据张贴到控制器操作是不容易的。我建议您使用标准的html提交按钮将现有的视图html包装在BeginForm语句中：

@using(Html.BeginForm("AddNewSkill","YourControllerName", FormMethod.Post))
{
    // ...your existing markup with the properties of the model here...
    <button type="submit">Add Skill</button>
}

这应该会将您的所有模型属性发布到控制器操作中。您应该注意，MVC ModelBinder会将各种属性"重新组装"（从技术上讲：绑定）到服务器端的模型。

IOW您不需要尝试将模型作为一个完整的对象发送，就像您试图使用RouteValues一样——就像在中一样

CCD_ 2。

希望能有所帮助。

ActionLink 上提到的Id在哪里

@Html.ActionLink("Add Skill", "AddNewSkill", new { skill = Model, id = ViewBag.professionalId} )

参数名称应与操作结果参数匹配。所以将你的行动链接更改为以下

@Html.ActionLink("Add Skill", "AddNewSkill", new { skill = Model, professionalId = ViewBag.professionalId} )

这应该工作

欢呼

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