视图模型的参数在回发中为空

Question

我知道这个问题被问了很多次，但不幸的是，没有一个答案对我有帮助。

我有树型POCO模型，它们是Pharmacy、Address和Company，汇集在一起形成ViewModel PharmacyVM:

public class PharmacyVM
{
public Pharmacy pharmacyProp { get; set; }
public Address addressProp { get; set; }
public Company companyProp { get; set; }
public int CityId { get; set; }
public PharmacyVM()
{
pharmacyProp = new Pharmacy();
addressProp = new Address();
companyProp = new Company();
}
}

不要嘲笑房产名称；一开始，它们是正常的(地址、公司和药房)我根据这里的很多答案之一更改了它们，但是。。。它没有帮助：(

在Create方法的Get操作中，我试图手动创建PharmacyVM对象并将其传递给视图：

public ActionResult Create()
{
ViewBag.CityId = new SelectList(db.Cities, "Id", "Name");
ViewBag.CompanyId = new SelectList(db.Companies, "Id", "Name");
ViewBag.AddressId = new SelectList(db.Addresses, "Id", "Name");
ViewBag.CityId = new SelectList(db.Cities, "Id", "Name");
ViewBag.RegionId = new SelectList(db.Regions, "Id", "Name");
ViewBag.DistrictId = new SelectList(db.Districts, "Id", "Name");
ViewBag.MicrodistrictId = new SelectList(db.Microdistricts, "Id", "Name");
ViewBag.StreetId = new SelectList(db.Streets, "Id", "Name");
ViewBag.VillageId = new SelectList(db.Villages, "Id", "Name");
var pharmacyVM = new PharmacyVM();
return View(pharmacyVM);
}

视图中有一个标准的Razor代码：

@model MEDONET.Models.PharmacyVM
@{
ViewBag.Title = "Create";
}
<h2>Create</h2>
@using (Html.BeginForm("Create", "Pharmacies", FormMethod.Post, new { enctype = "multipart/form-data" }))
{
@Html.AntiForgeryToken()
<div class="form-horizontal">
<h4>pharmacyProp</h4>
<hr />
@Html.ValidationSummary(true, "", new { @class = "text-danger" })
<div class="form-group">
@Html.LabelFor(model => model.companyProp, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("CompanyId", null, "", htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.companyProp.Id, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.pharmacyProp.Name, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.pharmacyProp.Name, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.pharmacyProp.Name, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.addressProp.City, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("CityId", null, "", htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.CityId, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.CityId, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("CityId", null, "", htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.CityId, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.addressProp.Village, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("VillageId", null, "", htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.addressProp.VillageId, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.addressProp.District, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("DistrictId", null, "", htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.addressProp.DistrictId, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.HiddenFor(model => model.addressProp.RegionId)
@Html.LabelFor(model => model.addressProp.Region, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("RegionId", null, "", htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.addressProp.RegionId, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.addressProp.Microdistrict, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("MicrodistrictId", null, "", htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.addressProp.MicrodistrictId, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.addressProp.Building, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.addressProp.Building, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.addressProp.Building, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.addressProp.Street, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("MicrodistrictId", null, "", htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.addressProp.MicrodistrictId, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.pharmacyProp.IsGov, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
<div class="checkbox">
@Html.EditorFor(model => model.pharmacyProp.IsGov)
@Html.ValidationMessageFor(model => model.pharmacyProp.IsGov, "", new { @class = "text-danger" })
</div>
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.companyProp, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("companyId", null, "", htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.pharmacyProp.CompanyId, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.pharmacyProp.LargeImage, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
<input type="file" name="LargeImageFile" required />
</div>
</div>

<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Create" class="btn btn-default" />
</div>
</div>
</div>
}
<div> @Html.ActionLink("Back to List", "Index")</div>
@section Scripts {
@Scripts.Render("~/bundles/jqueryval")
}

然后在Create方法的Post操作中，我试图创建b和c变量：

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(PharmacyVM model, HttpPostedFileBase LargeImageFile)
{
if (ModelState.IsValid)
{
string LargeImageFileName = Path.GetFileNameWithoutExtension(LargeImageFile.FileName);
string LargeImageExtansion = Path.GetExtension(LargeImageFile.FileName);
LargeImageFileName = LargeImageFileName + DateTime.Now.ToString("yymmssfff") + LargeImageExtansion;
LargeImageFileName = Path.Combine(Server.MapPath("~/Images/Pharmacy/Banners/"), LargeImageFileName);
int b = model.CityId;
int c = model.addressProp.RegionId.Value;
//Address address = new Address()
//{
//    Id = 12,//db.Addresses.AsEnumerable().Last().Id + 1,
//    RegionId = PharmacyVM.Address.RegionId,
//    DistrictId = PharmacyVM.Address.DistrictId,
//    CityId = PharmacyVM.Address.CityId,
//    MicrodistrictId = PharmacyVM.Address.MicrodistrictId,
//    StreetId = PharmacyVM.Address.StreetId,
//    VillageId = PharmacyVM.Address.VillageId,
//    Building = PharmacyVM.Address.Building,
//    Cab = PharmacyVM.Address.Cab
//};
//Address address = new Address
//{
//    Id = 12,//db.Addresses.AsEnumerable().Last().Id + 1,
//    RegionId = 1,
//    DistrictId = 1,
//    CityId = 1,
//    MicrodistrictId = 1,
//    StreetId = 1,
//    VillageId = 1,
//    Building = "1",
//    Cab = "1"
//};
//db.Addresses.Add(address);
db.SaveChanges();
var pharmacy = new Pharmacy
{
Name = model.pharmacyProp.Name,
//AddressId = address.Id,
IsGov = model.pharmacyProp.IsGov,
CompanyId = model.pharmacyProp.CompanyId,
LargeImage = "~/Images/Pharmacy/Banners/" + LargeImageFileName
};
LargeImageFile.SaveAs(LargeImageFileName);
db.Pharmacies.Add(pharmacy);
db.SaveChanges();
ModelState.Clear();
return RedirectToAction("Index");
}
}

与第一个变量b不同，第二个变量c将是null，因为addressProp属性是

null为什么这么奇怪？如何使用ViewModel而不复制原始模型的字段

Answer 1

为什么要使用

int b= model.addressProp.RegionId.Value

而不是

int b=model.addressProp.RegionId

即使是为了你的记录，最好的方法也是移除所有View包和将所有查看包属性添加到PharmacyVM类不要将两个属性用于视图绑定

示例

public class PharmacyVM
{
public Pharmacy pharmacyProp { get; set; }
public Address addressProp { get; set; }
public Company companyProp { get; set; }
public int CityId { get; set; }
public SelectList CityIdList { get; set; }     
public PharmacyVM()
{
pharmacyProp = new Pharmacy();
addressProp = new Address();
companyProp = new Company();
CityIdList =new SelectList(db.Cities, "Id", "Name");
}
}
public ActionResult Create()
{ 
var pharmacyVM = new PharmacyVM();
return View(pharmacyVM);
}
@model PharmacyVM
@using (Html.BeginForm())
{
@Html.HiddenFor(m => m.CityId )
<div class="editor-label">
@Html.LabelFor(m => m.Name)
</div>
<div class="editor-field">
@Html.EditorFor(m => m.Name)
@Html.ValidationMessageFor(m => m.Name)
</div> 
<button type="submit">Create</button>
}
[HttpPost]
public ActionResult Create(PharmacyVM model)
{
int c = model.addressProp
return View(viewModel);
}

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