Question

我创建了viewmodel视图，允许我在我的视图中使用2模型（Fax＆amp; Faxdata）但我在listboxfor中有SelectedEmployees的NULL值我的viewmodel中有什么问题？

 namespace FaxProject.ViewModel
{
public class SendFaxVm
{

    public List<SelectListItem> Employees { set; get; }

    public int[] SelectedEmployees { set; get; }
    public Fax fax { set; get; }

  }
}

这是视图（Edite视图）

@model FaxProject.ViewModel.SendFaxVm

    @using (Html.BeginForm("Edit","Fax"))
      {
      @Html.AntiForgeryToken()

<div class="form-horizontal">
    <h4>Fax</h4>
    <hr />
    @Html.ValidationSummary(true, "", new { @class = "text-danger" })
    @Html.HiddenFor(model => model.fax.Id)

    <div class="form-group">
        @Html.LabelFor(model => model.fax.Courier_Num, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.fax.Courier_Num, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.fax.Courier_Num, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.fax.NumberOfPages, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.fax.NumberOfPages, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.fax.NumberOfPages, "", 
    <div class="form-group">
        @Html.LabelFor(model => model.Employees, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">

            @Html.ListBoxFor(a => a.SelectedEmployees, Model.Employees)
            @Html.ValidationMessageFor(a => a.SelectedEmployees)


        </div>
    </div>

    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="Back" class="btn btn-default" />
        </div>
    </div>
</div>

}

我在列表框中得到了null异常所以如何获得编辑它的员工列表？

 public ActionResult Edit (int id,SendFaxVm vm,Fax fax)
    {
        var faxindb = Db.Faxes.Single(f=>f.Id==id);
        faxindb.Courier_Num = fax.Courier_Num;
        faxindb.NumberOfPages = fax.NumberOfPages;
        faxindb.CompanyName = fax.CompanyName;
        faxindb.ReceivingDate = fax.ReceivingDate;
        faxindb.Attachment = fax.Attachment;
        faxindb.Subject = fax.Subject;
        Db.SaveChanges();

        foreach (var userId in vm.SelectedEmployees)
        {
            var faxdataindb = Db.FaxDatas.Single(f => f.FaxId == fax.Id);
            faxdataindb.EmpId = userId;
            //to do  : Save fd 

            Db.SaveChanges();
        }

        return RedirectToAction("FaxForm","Fax");
    }

这是传真控制器中的操作...

Answer 1

嘿，你可以改善几件事。

public class SendFaxVm
{
    public List<SelectListItem> Employees { set; get; }
    public List<int> SelectedEmployees { set; get; }
    public Fax fax { set; get; }

  }

将数组更改为模型中的List，您也可以在此处使用IEnumerable。如果您，也请按照此示例填充列表框https://www.codeproject.com/Articles/771999/ASP-Net-MVC-How-to-create-a-ListBox

我想更新传真和员工表之间链接的传真表和FaxData表

1 个答案: