如何将项目列表从视图传递到控制器 (ASP.NET MVC 4)

Question

I'm trying to pass multiple items of type List<item> to my controller, however, when I submit my data, it show as null in my controller.

What I would like to happen is that I have a list of 'expenses' in the View, and beside each 'expense' or item is a checkbox from the Submitted Boolean property in my Model. When I check the items, I would like the list of checked items' properties Submitted and DateSubmitted to be updated in the database.

@Html.DisplayFor(modelItem => item.Submitted) in the View produces checkboxes.

What am I doing wrong?

Here is my View:

@model IEnumerable<Expenses.Models.Expense>

@{
ViewBag.Title = "Submit Expenses";
Layout = "~/Views/Shared/_Layout.cshtml";

DateTime today = DateTime.Today;
string formattedDate = today.ToString("MM/dd/yyyy");
}

<link rel="stylesheet" href="//code.jquery.com/ui/1.11.4/themes/smoothness/jquery-ui.css">
<script src="//code.jquery.com/jquery-1.10.2.js"></script>
<script src="//code.jquery.com/ui/1.11.4/jquery-ui.js"></script>

<h2>Submit Expenses</h2>

@using (Html.BeginForm())
{
@Html.AntiForgeryToken()
<div class="form-inline">
    <div class="form-group">
        <h4>Start Date:</h4>
        <div class="col-md-10">
            @Html.TextBox("expenseDate", formattedDate, htmlAttributes: new
           {
               @class = "form-control"
           })
        </div>
    </div>

    <div class="form-group">
        <h4>End Date:</h4>
        <div class="col-md-10">
            @Html.TextBox("expenseDate2", formattedDate, htmlAttributes: new
           {
               @class = "form-control"
           })
        </div>
    </div>

    <div class="form-group">
        @if (User.IsInRole("admin"))
        {
            <h4>Username:</h4>
            <div class="editor-field">
                @Html.DropDownList("UserId", String.Empty)
            </div>
        }
    </div>

    <br />
    <br />

    <div class="form-group">
        <div class="col-md-2">
            <input type="submit" value="Retrieve Expenses" class="btn btn-default" />
        </div>
    </div>

</div>

<br />
<br />


<p>
    @Html.ActionLink("Create New", "Create")
</p>
<table style="margin-bottom: 20px;">
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.Company)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Category)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Province)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.ReceiptName)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Comment)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.GrossAmount)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.TaxAmount)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.NetAmount)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Mileage)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.TravelStatus)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.LunchLearnStatus)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.WithClientStatus)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.DateEntered)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.DateSubmitted)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.ExpenseDate)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.ImageName)
        </th>
        @if (User.IsInRole("admin"))
        {
            <th>
                @Html.DisplayNameFor(model => model.UserProfile.UserName)
            </th>
        }
        <th></th>
    </tr>
    <tr>
        <td>
            <b>Select All:</b>
            <br />
            <input type="checkbox" name="expense" value="Expense" id="selectAllCheckboxes" class="expenseCheck">
        </td>
    </tr>
    @foreach (var item in Model)
    {
        <tr>
            <td class="submitCheck">
                @Html.EditorFor(modelItem => item.Submitted)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Company)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Category)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Province)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.ReceiptName)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Comment)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.GrossAmount)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.TaxAmount)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.NetAmount)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Mileage)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.TravelStatus)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.LunchLearnStatus)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.WithClientStatus)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.DateEntered)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.DateSubmitted)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.ExpenseDate)
            </td>
            <td>
                @if (item.ImageName != null)
                {
                    <a href="~/Images/@Html.DisplayFor(modelItem => item.UserProfile.FullName)/@Html.DisplayFor(modelItem => item.ImageName)" class="imageClick" target="_blank"><img src="~/Images/@Html.DisplayFor(modelItem => item.UserProfile.FullName)/@Html.DisplayFor(modelItem => item.ImageName)" alt="Image" style="width:80%" /></a>
                }
            </td>
            @if (User.IsInRole("admin"))
            {
                <td>
                    @Html.DisplayFor(modelItem => item.UserProfile.UserName)
                </td>
            }
            <td>
                @Html.ActionLink("Edit", "Edit", new { id = item.ExpenseId }) |
                @Html.ActionLink("Details", "Details", new { id = item.ExpenseId }) |
                @if (User.IsInRole("admin"))
                {
                    @Html.ActionLink("Delete", "Delete", new { id = item.ExpenseId })
                }

            </td>
        </tr>
    }

</table>

 @Html.ActionLink("Submit Expenses", "SubmitExpenses", "Expenses", null, new { @class = "submitLink", @style = "background-color: #d3dce0; border: 1px solid #787878; cursor: pointer; font-size: 1.5em; font-weight: 600; margin-right: 8px; padding: 7px; width: auto; text-decoration: none; font-weight:bold;"})

<div class="ExportSection" style="margin-top:30px;">
    @*<a href="javascript:void(0)">Export To CSV</a>*@
    @Html.ActionLink("Export To CSV", "ExportExpensesListToCSV")
</div>
}

@section scripts {
<script type="text/javascript">


    $("#selectAllCheckboxes").click(function () {
        $('.submitCheck input:checkbox').not(this).prop('checked', this.checked);
    });

    $(function () {
        $("#expenseDate").datepicker();
    });

    $(function () {
        $("#expenseDate2").datepicker();
    });

</script>

}

and here is my Controller method:

public ActionResult SubmitExpenses(List<Expense> expenses, DateTime? expenseDate = null, DateTime? expenseDate2 = null, int? userId = 0)
    {
        expenseDate = (DateTime)Session["FirstDate"];
        expenseDate2 = (DateTime)Session["SecondDate"];

        if (expenseDate == null || expenseDate2 == null)
        {
            expenseDate = DateTime.Now.AddMonths(-1);
            expenseDate2 = DateTime.Today;
        }

        string currentUserId = User.Identity.Name;

        var query = from e in db.Expenses
                    join user in db.UserProfiles on e.UserId equals user.UserId
                    where e.ExpenseDate >= expenseDate && e.ExpenseDate <= expenseDate2 && e.DateSubmitted == null
                    orderby e.ExpenseDate descending
                    select new { e, user };

        if (User.IsInRole("admin") && userId != 0)
        {
            query = query.Where(x => x.user.UserId == userId);
        }
        else if (!User.IsInRole("admin"))
        {
            query = query.Where(x => x.user.UserName == currentUserId);
        }

        var expensesFromView = expenses;

        var joined = from dbExpense in query.Select(x => x.e).AsEnumerable()
                     join localExpense in expenses on dbExpense.ExpenseId equals localExpense.ExpenseId
                     where localExpense.Submitted
                     select dbExpense;

        foreach (Expense exp in joined)
        {
            exp.DateSubmitted = DateTime.Today;
        }

        try
        {
            db.SaveChanges();
            return RedirectToAction("Index");
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
            return RedirectToAction("Submit");
        }

    }

Here is my model:

[Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int ExpenseId { get; set; }

    [Required]
    public string Company { get; set; }

    [Required]
    public string Category { get; set; }

    [Required]
    [Display(Name = "Receipt Name")]
    public string ReceiptName { get; set; }
    public string Comment { get; set; }

    [Required]
    public string Province { get; set; }

    [Required]
    [Display(Name = "Gross Amount")]
    public decimal GrossAmount { get; set; }

    [Required]
    [Display(Name = "GST/HST Amount")]
    public decimal TaxAmount { get; set; }

    [Required]
    [Display(Name = "Net Amount")]
    public decimal NetAmount { get; set; }

    [Display(Name = "Mileage (in Kilometers)")]
    public int Mileage { get; set; }

    [Display(Name = "Travelling?")]
    public bool TravelStatus { get; set; }

    [Display(Name = "Lunch & Learn?")]
    public bool LunchLearnStatus { get; set; }

    [Display(Name = "With Clients?")]
    public bool WithClientStatus { get; set; }

    [DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}")]
    [Required]
    [Display(Name = "Date Entered")]
    public DateTime? DateEntered{ get; set; }

    [DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}")]
    [Display(Name = "Date Submitted")]
    public DateTime? DateSubmitted { get; set; }

    [DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}")]
    [Required]
    [Display(Name = "Expense Date")]
    public DateTime? ExpenseDate { get; set; }

    [Display(Name = "Image")]
    public string ImageName { get; set; }

    [Display(Name = "Submitted?")]
    public bool Submitted { get; set; }

    [Required]
    [Display(Name = "Name")]
    public int UserId { get; set; }
    [ForeignKey("UserId")]
    public virtual UserProfile UserProfile { get; set; }

My variable expensesFromView is showing as null and as a result, I get an error on my joined query that says:

Value cannot be null. Parameter name: inner

Answer 1

There are two ways to do this -

1 .

You might need this extension which is really good and extensible- MvcCheckBoxList -- SEEMS this site has been shut down :) refer the option 2

2 .

@for (int i = 0; i < Model.Count; i++)
{

     <tr>
      <td class="submitCheck">
       <input type="checkbox" value="@Model[i].Id" name="Expense[@i].Id">
       <input type="hidden" value="0" name="Expense[@i].Id">          
      </td>
      <td>
          @Html.DisplayFor(modelItem => item.Company)
      </td>
     </tr>
}

btw: if you use the second way : in your controller, filter for the zero value of for the expense object's Id; coz if it is not selected, zero is sent to the controller (as the element's ID) grace to the "hidden" field you can see in the above code.

Answer 2

I couldn't really find a way to pass a list of items directly from View to Controller, so I decided to use AJAX.

I changed the parameters of my Controller from type List<> to int[ ] to take an array of item IDs:

public ActionResult SubmitExpenses(int[] expenseIDs, DateTime? expenseDate = null, DateTime? expenseDate2 = null, int? userId = 0)
    {
        expenseDate = (DateTime)Session["FirstDate"];
        expenseDate2 = (DateTime)Session["SecondDate"];

        if (expenseDate == null || expenseDate2 == null)
        {
            expenseDate = DateTime.Now.AddMonths(-1);
            expenseDate2 = DateTime.Today;
        }

        string currentUserId = User.Identity.Name;

        var query = from e in db.Expenses
                    join user in db.UserProfiles on e.UserId equals user.UserId
                    where e.ExpenseDate >= expenseDate && e.ExpenseDate <= expenseDate2 && e.DateSubmitted == null
                    orderby e.ExpenseDate descending
                    select new { e, user };

        if (User.IsInRole("admin") && userId != 0)
        {
            query = query.Where(x => x.user.UserId == userId);
        }
        else if (!User.IsInRole("admin"))
        {
            query = query.Where(x => x.user.UserName == currentUserId);
        }

        //var localExpenseIDs = expenseIDs;

        var joined = from dbExpense in query.Select(x => x.e).AsEnumerable()
                     join localExpense in expenseIDs on dbExpense.ExpenseId equals localExpense
                     where localExpense == dbExpense.ExpenseId
                     select dbExpense;

        foreach (Expense exp in joined)
        {
            exp.DateSubmitted = DateTime.Today;
            exp.IsSubmitted = true;
        }

        try
        {
            db.SaveChanges();
            return RedirectToAction("Index");
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
            return RedirectToAction("Submit");
        }

    }

In my view, I assigned the ID of each item to the id of it's own HTML checkbox :

@foreach (var item in Model)
    {
        <tr>
            <td class="checkbox-td">
                @Html.CheckBox("isSubmitted", new
           {
               @id = @Html.DisplayFor(modelItem => item.ExpenseId),
               @class = "submitBox"
           })
            </td>
        </tr>
     }

<div>
    @Html.ActionLink("Submit Expenses", "", "", null, new { @id = "submitExpensesLink" })
</div>

I wrote some jQuery, so that each checkbox that is checked, will add the id of the input element to an array and the array of integers would be POSTed to the SubmitExpenses action:

var checkedArray = [];

    $(':checkbox[name=isSubmitted]').on('change', function () {

        checkedArray = $(':checkbox[name=isSubmitted]:checked').map(function () {
                return this.id;
         })
        .get();


        //alert(checkedArray);
    });

    $('#submitExpensesLink').click(function () {

        $.ajax({
            type: "POST",
            traditional: true,
            url: "@Url.Action("SubmitExpenses", "Expenses")",
            data: { expenseIDs: checkedArray },
        success: function () {
            alert("Success!");
        },
        error: function (XMLHttpRequest, textStatus, errorThrown) {
            if (debug) {
                alert(XMLHttpRequest.responseText);
                alert(textStatus);
                alert(errorThrown);
            }
        }
    });
    })

Answer 3

1) Add FormMethod.Post into @using (Html.BeginForm()) {}

@using (Html.BeginForm("nameAction", "nameController", FormMethod.Post))
{
   //Your  code
}

2) You should to add name for inputs like this :

<input type="text" name="someName"/>