MVC 4 - 未将对象引用设置为对象的实例。当 POST 操作并索引每一行

Question

这个问题我有两个问题

我想 post 每行 table 但是当我 post 我得到这个错误：

Object reference not set to an instance of an object. when POST action

在这段代码中：

foreach (var p in hdrdtl.TBHDR)

VS 评论 hdrdtl.TBHDR 有问题。

我该如何解决这个问题？

我的模型class:

namespace Mvc_CSS.Models
{
    public class HeaderDetailModels
    {
        public virtual List<TB_RST_SVCHDR> TBHDR { get; set; }
        public virtual List<TB_RST_SVCDTL> TBDTL { get; set; }
    }
}

控制器

public ActionResult Index()
{
    var hdrdtl = new HeaderDetailModels
        {
            TBHDR = new List<Mvc_CSS.TB_RST_SVCHDR> { new TB_RST_SVCHDR { REQ_NO = 0, REQUESTOR_EMPNAME = "", REQUESTOR_EMPNO = "", DEPT_CD = "", ORG_NAME = "", EMAIL_ID = "", APPROVER1 = "", APPROVER2 = "", TOTAL_AMOUNT = 0, REQUEST_DATE = DateTime.Now, APPROVAL_DATE = DateTime.Now, EVENT_DATE = DateTime.Now, EVENT_PLACE = "", PURPOSE = "", REMARKS = "", STATUS = "", EXT = "" } },
            TBDTL = new List<Mvc_CSS.TB_RST_SVCDTL> { new TB_RST_SVCDTL { REQ_NO = 0, SEQ_NO = 0, ITEM_ID = 0, QUANTITY = 0, UOM = "", UNIT_PRICE = 0, EXTENDED_AMT = 0 } },
        };
        
    // List<Mvc_CSS.TB_RST_SVCHDR> hdr = new List<Mvc_CSS.TB_RST_SVCHDR> { new TB_RST_SVCHDR { REQ_NO = 0, REQUESTOR_EMPNAME = "", REQUESTOR_EMPNO = "", DEPT_CD = "", ORG_NAME = "", EMAIL_ID = "", APPROVER1 = "", APPROVER2 = "", TOTAL_AMOUNT = 0, REQUEST_DATE = DateTime.Now, APPROVAL_DATE = DateTime.Now, EVENT_DATE = DateTime.Now, EVENT_PLACE = "", PURPOSE = "", REMARKS = "", STATUS = "", EXT = "" } };

    Entities db = new Entities();

    return View(hdrdtl);
}

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Index(HeaderDetailModels hdrdtl)
{
    Entities db = new Entities();

    if (ModelState.IsValid)
    {
        using (Entities cd = new Entities())
        {
            foreach (var p in hdrdtl.TBHDR)
            {
                p.STATUS = "N";
                p.CRT_DATE = DateTime.Now;
                p.APPROVER3 = "saul.gomez@lge.com";
                cd.TB_RST_SVCHDR.Add(p);
            }

            cd.SaveChanges();
            ModelState.Clear();

            hdrdtl = new HeaderDetailModels
                {
                    TBHDR = new List<Mvc_CSS.TB_RST_SVCHDR> { new TB_RST_SVCHDR { REQ_NO = 0, REQUESTOR_EMPNAME = "", REQUESTOR_EMPNO = "", DEPT_CD = "", ORG_NAME = "", EMAIL_ID = "", APPROVER1 = "", APPROVER2 = "", TOTAL_AMOUNT = 0, REQUEST_DATE = DateTime.Now, APPROVAL_DATE = DateTime.Now, EVENT_DATE = DateTime.Now, EVENT_PLACE = "", PURPOSE = "", REMARKS = "", STATUS = "", EXT = "" } },
                    TBDTL = new List<Mvc_CSS.TB_RST_SVCDTL> { new TB_RST_SVCDTL { REQ_NO = 0, SEQ_NO = 0, ITEM_ID = 0, QUANTITY = 0, UOM = "", UNIT_PRICE = 0, EXTENDED_AMT = 0 } },
                };
        }
    }

    return View(hdrdtl);
}

查看

@model Mvc_CSS.Models.HeaderDetailModels

@using (Html.BeginForm("Index","Home", FormMethod.Post, new { id = "fdata" }))
{ 
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)

    <table>
        @if (Model != null && Model.TBHDR.Count > 0)
        {
            int m = 0;
            foreach (var p in Model.TBHDR)
            {
        <thead>
            <th>Date & Time Requested</th>
            <th>Purpose</th>
            <th>Extension</th>
        </thead>
        <tbody>
            <td>@Html.TextBoxFor(mod => p.REQUEST_DATE)</td>
            <th>@Html.TextBoxFor(mod => p.PURPOSE)</th>
            <th>@Html.TextBoxFor(mod => p.EXT)</th>
            <th></th>
            <th></th>
        </tbody>
                m++;
            }
        }
    </table>
            <center><input type="submit" value="Submit Request" id="semail"/></center>
    
}
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
}

如何索引 table 中的每一行？

我知道问题太多，但感谢您的支持

Answer 1

尝试用for循环替换foreach循环

   for (var i=0; i< Model.TBHDR.Count; i++)
   {
             ....

            <td>@Html.TextBoxFor(model => model.TBHDR[i].REQUEST_DATE)</td>
            <th>@Html.TextBoxFor(model => model.TBHDR[i].PURPOSE)</th>
            <th>@Html.TextBoxFor(model => model.TBHDR[i].EXT)</th>
           ....

MVC 4 - 未将对象引用设置为对象的实例。当 POST 操作并索引每一行

MVC 4 - Object reference not set to an instance of an object. when POST action and index each row

c#

.net

asp.net-mvc

asp.net-mvc-4