Question

嗨


我在下面列出了以下型号和控制器


我尝试通过foreignkey在视图创建中引入下拉列表     ＆＃34;标题＆＃34;但我无法在创建/保存中获得错误

请帮助代码 - （我是初学者）

     imprumutsController.cs
        ....
           // GET: imprumuts/Create
                public ActionResult Create()
                {

                    ViewBag.idcarti_stoc = new SelectList(db.carti_stoc, "idcarti", "idcarti" );
                    ViewBag.idcititor = new SelectList(db.citiors, "Idcititor", "Numele");
                    // ViewBag.idcititor = new SelectList(db.cartis, "Idcarti", "Titlu");
                     ViewBag.idcarti = new SelectList(db.cartis, "Idcarti", "Titlu");

                    return View();
                }

            // POST: imprumuts/Create
            [enter image description here][1]
            [HttpPost]
            [ValidateAntiForgeryToken]
            public ActionResult Create([Bind(Include = "Idimprumut,idcarti_stoc,idcititor,data_imprumut,durata,data_restituire")] imprumut imprumut)
            {
                if (ModelState.IsValid)
                {
                    db.imprumuts.Add(imprumut);
                    db.SaveChanges();
                    return RedirectToAction("Index");
                }

                ViewBag.idcarti_stoc = new SelectList(db.carti_stoc, "idcarti_stoc", "idcarti_stoc", imprumut.carti_stoc.carti.Titlu);
                // ViewBag.idcart_stoc = new SelectList(db.carti_stoc, "idcarti_stoc", "idcarti_stoc", imprumut.idcarti_stoc);
                // ViewBag.idcititor = new SelectList(db.citiors, "Idcititor", "idcititor", imprumut.idcititor);
                return View(imprumut);
            }



     imprumuts - Create.cshtml
         ...
        @*  @Html.LabelFor(model => model.idcarti_stoc, "idcarti_stoc", htmlAttributes: new { @class = "control-label col-md-2" })
            *@
                 @Html.LabelFor(model => model.idcarti_stoc, "Titlu", htmlAttributes: new { @class = "control-label col-md-2" })
                <div class="col-md-10">
                    @Html.DropDownList("idcarti", null, htmlAttributes: new { @class = "form-control" })
                    @Html.ValidationMessageFor(model => model.idcarti_stoc, "", new { @class = "text-danger" })
                </div>
            </div>

   namespace carti_v2.Models
    {
        using System;
        using System.Collections.Generic;
        using System.ComponentModel.DataAnnotations;

        public partial class imprumut
        {
            public int Idimprumut { get; set; }
            public int idcarti_stoc { get; set; }
            public int idcititor { get; set; }

            [DataType(DataType.Date)]
            [DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true)]
            public System.DateTime data_imprumut { get; set; }

            public int durata { get; set; }
            public Nullable<System.DateTime> data_restituire { get; set; }

            public virtual carti_stoc carti_stoc { get; set; }
            public virtual citior citior { get; set; }
        }
    }


        namespace carti_v2.Models
    {
        using System;
        using System.Collections.Generic;

        public partial class carti_stoc
        {
            [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
            public carti_stoc()
            {
                this.imprumuts = new HashSet<imprumut>();
            }

            public int idcarti_stoc { get; set; }
            public int idcarti { get; set; }
            public bool disponibil { get; set; }

            public virtual carti carti { get; set; }
            [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
            public virtual ICollection<imprumut> imprumuts { get; set; }
        }
    }

*****

    namespace carti_v2.Models
    {
        using System;
        using System.Collections.Generic;

        public partial class carti
        {
            [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
            public carti()
            {
                this.carti_stoc = new HashSet<carti_stoc>();
            }

            public int idcarti { get; set; }
            public string Autor { get; set; }
            public string Titlu { get; set; }
            public string Domeniu { get; set; }
            public string ISBN { get; set; }

            [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
            public virtual ICollection<carti_stoc> carti_stoc { get; set; }

Answer 1

请记住，如果某个字段上有外键，那么该字段需要在主字段中具有匹配值。

你需要放置单独的SaveChanges（）以便关系一致。像FK_imprumut_carti_stoc失败意味着一些carti_stoc imprumut字段不会出现在imprumut中

你可以这样做：

   public ActionResult Index63()
    {
        //use your dbcontext
        using (BreazEntities19 entity = new BreazEntities19())
        {
            //entity.SaveChanges();
            imprumut i = new imprumut
            {
                carti_stoc = 1,  //THIS Needs to be unique
                data_imprumut = DateTime.Parse("12/12/12"),
                data_restituire = DateTime.Parse("12/12/12"),
                durata = 1,
                idcarti_stoc = 1,
                idcititor = 1
            };
            entity.imprumuts.Add(i);
            entity.SaveChanges();

            carti_stoc cs = new carti_stoc
            {
                carti = 1, //THIS Needs to be unique
                disponibil = true,
                idcarti = 1,
                impromut = i.carti_stoc
            };
            entity.carti_stoc.Add(cs);
            entity.SaveChanges();

            carti c = new carti { Autor = "ap1", carti_stoc = cs.carti, Domeniu = "ap", ISBN = "ap", Titlu = "ap" };
            entity.cartis.Add(c);
            entity.SaveChanges();
        }

您可以在事务中包装所有内容：

using (TransactionScope scope = new TransactionScope())
                 {
                    //Put your work in here with multiple save changes
                    using (myDbcontext context = new myDbcontext()){
                        ...
                        context.SaveChanges();
                    }

                    scope.Complete();
                }

Answer 2

这是您的视图模型，使用您的命名空间：

namespace Testy20161006.Models
{
    public partial class carti
    {
        public string selectedItem {get; set;}
    }
}

这是你的控制器：

{
    [HttpPost]
    public ActionResult Index63(carti model)
    {
        //put a breakpoint here to see selected idcarte_stoc, as you want
        return View();
    }

    public ActionResult Index63()
    {
        //use your dbcontext name, be aware that you are not explicitely disposing of the obj
        BreazEntities19 entity = new BreazEntities19();
        SelectList selectList = new SelectList(entity.cartis, "carti_stoc", "Titlu");
        ViewBag.idcarti = selectList;

        return View();
    }

以下是您的观点：

@model Testy20161006.Models.carti

@{
    Layout = null;
}

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index63</title>

</head>
<body>
    @using (Html.BeginForm())
    {
         @Html.DropDownListFor(m => m.selectedItem,
                    new SelectList(ViewBag.idcarti, "Value", "Text"),
                    new { @class = "form-control" })
        <input type="submit" value="click" />
    }
</body>
</html>

Answer 3

这里是带有数据库结构的图像-diagram enter image description here

最终我认为应该通过idcarti和iscarti_stoc之间的链接下载级联。但我不知道如何从视图中检索选择的idcards，使控制器成为第二个选择......

asp.net mvc - 从foreignkey数据库创建下拉列表

3 个答案: