[英]Selected Value from DropdownList
I am trying to get the selected value from a dropdownlist which is populated from a database. 我正在尝试从数据库填充的下拉列表中获取选定的值。 The list populates fine and allows me to select a value, but when I click the submit button, I get an error that the list "is not set to instance of an object"
该列表可以很好地填充,并允许我选择一个值,但是当我单击“提交”按钮时,出现错误消息,该列表“未设置为对象的实例”
Here is my view: 这是我的看法:
@model LoanRequestRowViewModel
<h2>CreateTest</h2>
<div>
@using (@Html.BeginForm())
{
<div>
<span class="inline-block">
@Html.LabelFor(model => model.LoanPurpose)
@Html.DropDownListFor(model => model.LoanPurposeId, Model.LoanPurpose)
</span>
<span class="inline-block">
@Html.LabelFor(model => model.AmountRequested)
@Html.TextBoxFor(model => model.AmountRequested)
</span>
<span class="inline-block">
@Html.LabelFor(model => model.RequestedRate, new { @class = "control-label" })
@Html.TextBoxFor(model => model.RequestedRate, new { @class = "inputROW" })
</span>
</div>
<div>
<input type="submit" value="Create" />
</div>
}
</div>
Here is my controller: 这是我的控制器:
[HttpGet]
[Route("CreateTest")]
public async Task<ActionResult> CreateTest()
{
var loanPurposes = await GetLoanPurposes();
var model = new LoanRequestRowViewModel();
model.LoanPurpose.Add(new SelectListItem { Text = "-Please Select-", Value = "-1" });
foreach (var purpose in loanPurposes)
{
model.LoanPurpose.Add(new SelectListItem()
{
Value = purpose.Value.ToString(),
Text = purpose.Text.ToString()
});
}
return View(model);
}
[HttpPost]
[Route("CreateTest")]
public async Task<ActionResult> CreateTest(LoanRequestRowViewModel model)
{
var newLoan = new LoanRequest()
{
AmountRequested = model.AmountRequested,
LoanPurposeId = model.LoanPurposeId
};
return View();
}
Here is the Model: 这是模型:
public class LoanRequestRowViewModel
{
public LoanRequestRowViewModel()
{
LoanClasses = new List<SelectListItem>();
LoanTypes = new List<SelectListItem>();
LoanPurpose = new List<SelectListItem>();
RateIndex = new List<SelectListItem>();
PaymentPeriod = new List<SelectListItem>();
PaymentType = new List<SelectListItem>();
}
public Guid Id { get; set; }
public Guid LoanApplicationId { get; set; }
public Guid LoanPurposeId { get; set; }
public Guid LoanClassId { get; set; }
[Display(Name = "Loan Class")]
public IList<SelectListItem> LoanClasses { get; set; }
public string SelectedLoanClass { get; set; }
[Display(Name = "Loan Purpose")]
public IList<SelectListItem> LoanPurpose { get; set; }
public string SelectedLoanPurpose { get; set; }
[Display(Name = "Amount Requested")]
public decimal? AmountRequested { get; set; }
[Display(Name = "Requested Rate")]
public decimal? RequestedRate { get; set; }
[Display(Name = "Loan Type")]
public IList<SelectListItem> LoanTypes { get; set; }
public string SelectedLoanType { get; set; }
[Display(Name = "Rate Index")]
public IList<SelectListItem> RateIndex { get; set; }
public Guid SelectedRateIndex { get; set; }
[Display(Name = "Origination Fee")]
public decimal? OriginationFeePercentage { get; set; }
[Display(Name = "Variable Rate Margin")]
public decimal? VariableRateMargin { get; set; }
[Display(Name = "Variable Rate Floor")]
public decimal? VariableRateFloor { get; set; }
[Display(Name = "Variable Rate Ceiling")]
public decimal? VariableRateCeiling { get; set; }
[Display(Name = "Payment Type")]
public IList<SelectListItem> PaymentType { get; set; }
public string SelectedPaymentType { get; set; }
[Display(Name = "Payment Period")]
public IList<SelectListItem> PaymentPeriod { get; set; }
public int? SelectedPaymentPeriod { get; set; }
[Display(Name = "Number of Payments")]
public int? NumberOfPayments { get; set; }
[Display(Name = "Amortization Term")]
public decimal? AmortizationTerm { get; set; }
Any assistance is greatly appreciated! 非常感谢您的协助!
At your view you are expecting an viewmodel with information but you returning nothing to the view. 在您的视图上,您期望的是带有信息的视图模型,但是您不向视图返回任何内容。
@Html.DropDownListFor(model => model.LoanPurposeId, Model.LoanPurpose)
Asks for a filled list of loan purposes. 要求填写贷款目的清单。
But because the model is null, it simply crashes. 但是由于该模型为null,因此只会崩溃。
To solve this problem you need to pass a new instance of the model: LoanRequestRowViewModel 要解决此问题,您需要传递模型的新实例:LoanRequestRowViewModel
Also i would take to consideration to rename: Model.LoanPurpose. 我还要考虑重命名:Model.LoanPurpose。 It sounds to me that it just returns one property, not a list of items.
在我看来,它只返回一个属性,而不是项目列表。
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