我有一个主编辑页面，其中包含许多局部视图，当我尝试更新主编辑页面本身上的数据或其任何局部数据时，如果存在，则数据更新成功至少一个被调用部分的记录不保存，否则该操作给我这个错误：（当没有被调用部分的记录时）
ArgumentNullException：值不能为null。 参数名称：来源
主要型号：
public partial class Guests
{
public decimal Id { get; set; }
public string FName { get; set; }
public string SName { get; set; }
public string ThName { get; set; }
public string LName { get; set; }
[Required]
public string FullName { get; set; }
[DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:yyyy-MM-dd}")]
[Required]
public DateTime? BirthDate { get; set; }
[Required]
public int? SexId { get; set; }
[Required]
public int? HalaId { get; set; }
public string ImageUrl { get; set; }
public string UserId { get; set; }
public DateTime InsertDate { get; set; }
public string UpdateUser { get; set; }
public DateTime? UpdateDate { get; set; }
public Hala Hala { get; set; }
public Sex Sex { get; set; }
public ApplicationUser User { get; set; }
public IList<Visit> Visit { get; set; }
}
儿童访问模型：
public partial class Visit
{
public int Id { get; set; }
[Required]
public decimal GuestId { get; set; }
public DateTime VisitDate { get; set; }
public int? VisitTypeId { get; set; }
public bool SpecialStatus { get; set; }
public string Notes { get; set; }
public string UserId { get; set; }
public DateTime InsertDate { get; set; }
public string UpdateUser { get; set; }
public DateTime? UpdateDate { get; set; }
public Guests Guest { get; set; }
public VisitType VisitType { get; set; }
public ApplicationUser User { get; set; }
}
Guests控制器的post Edit方法：
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Edit(decimal id, [Bind("Id,FName,SName,ThName,LName,FullName,BirthDate,SexId,HalaId,KafalaId,ImageUrl,UserId,InsertDate,UpdateUser,UpdateDate,Visit")] Guests guest)
{
if (id != guest.Id)
{
return NotFound();
}
if (ModelState.IsValid)
{
try
{
var Edited = new Guests()
{
Id = guest.Id,
BirthDate = guest.BirthDate,
InsertDate = guest.InsertDate,
UserId = guest.UserId,
FullName = guest.FullName,
SexId = guest.SexId,
HalaId = guest.HalaId,
FName = guest.FName,
SName = guest.SName,
ThName = guest.ThName,
LName = guest.LName,
ImageUrl = guest.ImageUrl,
UpdateUser = guest.UpdateUser,
UpdateDate = guest.UpdateDate,
Visit = guest.Visit.Where(m => m.GuestId == guest.Id).ToList()/
};
_context.Update(Edited);
await _context.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!GuestsExists(guest.Id))
{
return NotFound();
}
else
{
throw;
}
}
return RedirectToAction(nameof(Index));
}
return View(guest);
}
客人编辑视图：
@model Guests
<meta charset="utf-8" dir="rtl">
<meta name="viewport" content="width=device-width, initial-scale=1">
<form asp-action="Edit">
<div asp-validation-summary="ModelOnly" class="text-danger"></div>
<input type="hidden" asp-for="Id" />
<input type="hidden" asp-for="InsertDate" />
<input type="hidden" asp-for="UserId" />
<input type="hidden" id="hdn_ha" asp-for="HalaId" />
<div class="row">
<div class="col-md-4">
<h3>Guest Edit</h3>
</div>
<div class="col-md-4">
</div>
</div>
<hr style="margin:0" />
<div class="row">
<div class="col-md-3">
<label asp-for="FullName" class="control-label">Full Name</label>
<input asp-for="FullName" class="form-control" readonly />
<span asp-validation-for="FullName" class="text-danger"></span>
</div>
<div class="col-md-3">
<label asp-for="BirthDate" class="control-label">Birth Date</label>
<input asp-for="BirthDate" class="form-control" readonly />
<span asp-validation-for="BirthDate" class="text-danger"></span>
</div>
<div class="col-md-3">
<label asp-for="SexId" class="control-label">Sex</label>
<select asp-for="SexId" class="form-control" asp-items="ViewBag.SexId"></select>
<span asp-validation-for="SexId" class="text-danger"></span>
</div>
<div class="col-md-3">
<label asp-for="HalaId" class="control-label">Hala</label>
<select asp-for="HalaId" class="form-control" id="ha" asp-items="ViewBag.HalaId" disabled></select>
<span asp-validation-for="HalaId" class="text-danger"></span>
</div>
</div>
<br />
<div>
<ul class="nav nav-tabs">
<li class="in active"><a data-toggle="tab" href="#home">Visits</a></li>
<li><a data-toggle="tab" href="#menu2">Another</a></li>
</ul>
<div class="tab-content">
@*<div id="home" class="tab-pane fade in active">
@{ await Html.RenderPartialAsync("~/Views/Visit/ParVisit.cshtml", Model); }
</div>
</div>
<div class="form-group">
<input type="submit" value="Save" class="btn btn-default" />
</div>
</form>
@section Scripts {
@{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}
<script src="https://code.jquery.com/jquery-1.11.0.min.js"></script>
<script>
$(document).ready(function () {
var select_ha = $('#ha option:selected').val();
$('#hdn_ha').val(select_ha);
});
</script>
ParVisit视图：
@model Guests
<a asp-action="Create" asp-controller="Visit">
<img src="~/images/icons8-add-new-480.png" style="background-color:blue" height="30" width="30" />
</a>
<table class="table">
<thead>
<tr>
<th>
Visit Date
</th>
<th>
Visit Type
</th>
<th>
Special Status
</th>
<th>
Notes
</th>
</tr>
</thead>
<tbody>
@for (var i = 0; i < Model.Visit.Count; ++i)
{
<tr>
@Html.HiddenFor(m => m.Visit[i].Id)
@Html.HiddenFor(m => m.Visit[i].GuestId)
@Html.HiddenFor(m => m.Visit[i].InsertDate)
@Html.HiddenFor(m => m.Visit[i].UpdateDate)
@Html.HiddenFor(m => m.Visit[i].UserId)
@Html.HiddenFor(m => m.Visit[i].UpdateUser)
@Html.HiddenFor(m => m.Visit[i].VisitTypeId)
@Html.HiddenFor(m => m.Visit[i].Guest)
<td width="15%">
@Html.EditorFor(m => m.Visit[i].VisitDate)
</td>
<td width="15%">
@Html.DropDownListFor(m => m.Visit[i].VisitTypeId, (SelectList)ViewBag.VisitTypeId)
</td>
<td width="15%">
@Html.EditorFor(m => m.Visit[i].SpecialStatus)
</td>
<td width="50%">
@Html.EditorFor(m => m.Visit[i].Notes)
</td>
</tr>
}
</tbody>
</table>
@section Scripts {
@{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}
现在，如果至少在Visit表中有一条记录，则该操作将正确保存更改，除非它给我这个错误：
ArgumentNullException: Value cannot be null. Parameter name: source
System.Linq.Enumerable.Where<TSource>(IEnumerable<TSource> source, Func<TSource, bool> predicate)
NozCoreWebApp7.Controllers.GuestsController.Edit(decimal id,
Guests guest) in GuestsController.cs
}
if (ModelState.IsValid)
{
try
{
var Edited = new Guests()
{
Id = guest.Id,
BirthDate = guest.BirthDate,
InsertDate = guest.InsertDate,
UserId = guest.UserId,
FullName = guest.FullName,
为什么？如何解决好吗？