将空列表从控制器传递到控制器ASP.NET MVC

Question

I Have a controller called CreateBoard that inserts the sessions and displays all of the sessions created in the database.My post version of this has no problem and is ok so I don't show it in the question.

[HttpGet]
public ActionResult CreateBoard(IEnumerable<BMModel> search)
{
    if (search != null)
    {
        ViewData["Boards"] = search;
        return View();
    }
    var db = new BoardMeetingEntities();
    var AllBoards = from p in db.tBoardMeetings
                    select new BMModel
                    {
                        Absent = p.Absent,
                        Attendent = p.Attendent,
                        BMDate = p.BMDate,
                        BMNo = p.BMNo.ToString(),
                        EndTime = p.EndTime,
                        StartTime = p.StartTime,
                        MPlace = p.MPlace,
                        IsFinal = p.IsFinal
                    };
    ViewData["Boards"] = AllBoards;
    return View();
}

public ActionResult SearchBoard(FormCollection form)
{
    string bmno = form["BMNo"].ToString();
    string bmdate = form["BMDate"].ToString();
    string mplace = form["MPlace"].ToString();
    if (bmno == string.Empty && bmdate == string.Empty && mplace == string.Empty)
    {
        return RedirectToAction("CreateBoard");
    }
    else
    {
        var db = new BoardMeetingEntities();
        var query = from p in db.tBoardMeetings
                    where p.BMNo.ToString() == bmno || p.BMDate.ToString() == bmdate || p.MPlace == mplace
                    select new BMModel
                    {
                        Absent = p.Absent,
                        Attendent = p.Attendent,
                        BMDate = p.BMDate,
                        BMNo = p.BMNo.ToString(),
                        EndTime = p.EndTime,
                        StartTime = p.StartTime,
                        MPlace = p.MPlace,
                        IsFinal = p.IsFinal
                    };
        IEnumerable<BMModel> q = query.ToList();
        return RedirectToAction("CreateBoard", new { search = q });
    }
}

And this is my view:

@model MetronicTemplate.Models.BMModel
@{
    ViewBag.Title = "BoardMeeting";
    IEnumerable<MetronicTemplate.Models.BMModel> list = ViewData["Boards"] as IEnumerable<MetronicTemplate.Models.BMModel>;
}


<div class="tab-content">
<div class="tab-pane active" id="tab_1">
    <div class="portlet box blue">
        <div class="portlet-title">
            <div class="caption"><i class="icon-reorder"></i> sessions</div>
            <div class="tools">
                <a href="javascript:;" class="collapse"></a>
                <a href="#portlet-config" data-toggle="modal" class="config"></a>
                <a href="javascript:;" class="reload"></a>
                <a href="javascript:;" class="remove"></a>
            </div>
        </div>
        <div class="portlet-body form">
            @using (Html.BeginForm())
            {


                if (ViewData["Success"] != null)
                {
                    <div class="alert alert-success fade in alert-dismissable" role="alert">
                        <p href="#" class="alert-link" data-dissmiss="alert">@ViewData["Success"].ToString()
                    </div>

                }
                @Html.ValidationSummary(true, "", new { @class = "alert-danger fade in alert-dismissable", role = "alert" })
                <h3 class="form-section">
                    insert session
                </h3>
                <div class="row-fluid">
                    <div class="span3 ">
                        <div class="control-group">
                            <label class="control-label">session number</label>
                            <div class="controls">
                                @Html.TextBoxFor(m => m.BMNo, "", new { @class = "m-wrap span12 medium", id ="BMNo" })
                            </div>
                            <div class="controls text-error">
                                @Html.ValidationMessageFor(m => m.BMNo, "", new { @class = "m-wrap span12" })
                            </div>
                        </div>
                    </div>
                    <div class="span6 ">
                        <div class="control-group">
                            <label class="control-label">date </label>
                            <div class="controls">
                                @Html.TextBoxFor(m => m.BMDate, "", new { @class = "m-wrap span12 medium", id ="BMDate" })
                            </div>
                            <div class="controls text-error">
                                @Html.ValidationMessageFor(m => m.BMDate, "", new { @class = "m-wrap span12" })
                            </div>
                        </div>
                    </div>
                </div>
                <div class="row-fluid">
                    <div class="span3 ">
                        <div class="control-group">
                            <label class="control-label">start session</label>
                            <div class="controls">
                                @Html.TextBoxFor(m => m.StartTime, "", new { @class = "m-wrap span12 medium", id ="BMStart" })
                            </div>
                            <div class="controls text-error">
                                @Html.ValidationMessageFor(m => m.StartTime, "", new { @class = "m-wrap span12" })
                            </div>
                        </div>
                    </div>
                    <div class="span3 ">
                        <div class="control-group">
                            <label class="control-label">end of session </label>
                            <div class="controls">
                                @Html.TextBoxFor(m => m.EndTime, "", new { @class = "m-wrap span12 medium", id ="BMEnd" })
                            </div>
                            <div class="controls text-error">
                                @Html.ValidationMessageFor(m => m.EndTime, "", new { @class = "m-wrap span12" })
                            </div>
                        </div>
                    </div>
                    <div class="span3 ">
                        <div class="control-group">
                            <label class="control-label">place of session </label>
                            <div class="controls">
                                @Html.TextBoxFor(m => m.MPlace, "", new { @class = "m-wrap span12", id ="BMPlace" })
                            </div>
                            <div class="controls text-error">
                                @Html.ValidationMessageFor(m => m.MPlace, "", new { @class = "m-wrap span12" })
                            </div>
                        </div>
                    </div>
                </div>

                <div class="row-fluid">
                    <div class="span6 ">
                        <div class="control-group">
                            <label class="control-label">attendent</label>
                            <div class="controls">
                                @Html.TextBoxFor(m => m.Attendent, "", new { @class = "m-wrap span12", id ="BMPresent" })
                            </div>
                            <div class="controls text-error">
                                @Html.ValidationMessageFor(m => m.Attendent, "", new { @class = "m-wrap span12" })
                            </div>
                        </div>
                    </div>
                    <div class="span6 ">
                        <div class="control-group">
                            <label class="control-label">absent </label>
                            <div class="controls">
                                @Html.TextBoxFor(m => m.Absent, "", new { @class = "m-wrap span12", id ="BMAbsent" })
                            </div>
                            <div class="controls text-error">
                                @Html.ValidationMessageFor(m => m.Absent, "", new { @class = "m-wrap span12" })
                            </div>
                        </div>
                    </div>
                </div>

                <div class="form-actions">
                    <button type="submit" class="btn blue"><i class="icon-ok"></i> insert</button>
                    <button type="button" class="btn" onclick="cancel()">cancel</button>
                    <button type="submit" class="btn" formaction="@Url.Action("SearchBoard","BoardMeeting")">search</button>
                </div>


                if (list != null)
                {
                    <h3>the list</h3>
                    <table class="table table-striped table-hover table-bordered dataTable" id="sample_editable_1" aria-describedby="sample_editable_1_info" style="width:1000px;">

                        <thead>
                            <tr role="row">
                                <th class="sorting_disabled" role="columnheader" rowspan="1" colspan="1" style="width:5px;" aria-label="Username">sessoin no</th>
                                <th class="sorting" role="columnheader" tabindex="0" aria-controls="sample_editable_1" rowspan="1" colspan="1" style="width: 15px;" aria-label="Full Name: activate to sort column ascending">session date</th>
                                <th class="sorting" role="columnheader" tabindex="0" aria-controls="sample_editable_1" rowspan="1" colspan="1" style="width: 15px;" aria-label="Points: activate to sort column ascending"> session start</th>
                                <th class="sorting" role="columnheader" tabindex="0" aria-controls="sample_editable_1" rowspan="1" colspan="1" style="width: 50px;" aria-label="Delete: activate to sort column ascending">end of session</th>
                                <th class="sorting" role="columnheader" tabindex="0" aria-controls="sample_editable_1" rowspan="1" colspan="1" style="width: 75px;" aria-label="Edit: activate to sort column ascending">place of session</th>
                                <th class="sorting" role="columnheader" tabindex="0" aria-controls="sample_editable_1" rowspan="1" colspan="1" style="width: 114px;" aria-label="Delete: activate to sort column ascending">attendent</th>
                                <th class="sorting" role="columnheader" tabindex="0" aria-controls="sample_editable_1" rowspan="1" colspan="1" style="width: 114px;" aria-label="Delete: activate to sort column ascending">absent</th>
                                <th class="sorting" role="columnheader" tabindex="0" aria-controls="sample_editable_1" rowspan="1" colspan="1" style="width: 114px;" aria-label="Delete: activate to sort column ascending">status</th>
                                <th class="sorting" role="columnheader" tabindex="0" aria-controls="sample_editable_1" rowspan="1" colspan="1" style="width: 50px;" aria-label="Delete: activate to sort column ascending"></th>
                            </tr>
                        </thead>
                        <tbody role="alert" aria-live="polite" aria-relevant="all">

                            @foreach (var item in list)
                            {
                                <tr class="odd">
                                    <td class="center">@item.BMNo.ToString()</td>
                                    <td class="center">@item.BMDate.ToString()</td>
                                    <td class="center">@item.MPlace</td>
                                    <td class="center">@item.StartTime</td>
                                    <td class="center">@item.EndTime</td>
                                    <td class="center">@item.Attendent</td>
                                    <td class="center">@item.Absent</td>
                                    <td class="center">
                                        <span class="center">
                                            <input class="checker" type="checkbox" readonly
                                                   @if (item.IsFinal) { @: checked
                                                                                                                                                                    } />
                                        </span>
                                    </td>

                                    <td class=" "><a class="center" href="@Url.Action("BMDetail", "BoardMeeting", new { id = @item.BMNo })">bmdetail</a></td>
                                    <td class=" "><a class="center" href="@Url.Action("Agenda", "BoardMeeting", new { id = @item.BMNo })">bmorder</a></td>
                                    <td class=" "><a class="center" href="@Url.Action("BMDetailActivity", "BoardMeeting", new { id = @item.BMNo, z = true })">session analyse</a></td>
                                    <td class=" "><a class="center" href="@Url.Action("FinalizeBoard", "BoardMeeting", new { FID = @item.BMNo })">finalize</a></td>
                                    <td class=" "><a class="edit" href="javascript:;">edit</a></td>
                                    <td class=" "><a class="delete" href="javascript:;">delete</a></td>
                                </tr>
                            }
                        </tbody>
                    </table>
                }
            }
        </div>
    </div>
</div>

My Problem is when I click the search button,it invokes the searchboard action and it queries the database perfectly but when it redirects to createboard action,the view displays nothing in the table.I traced the code and noticed that the query in the searchboard has no problem but when it comes to the createboard action,the search parameter has no value.Am I missing something?

Answer 1

Your controllers actions is just class methods, so insted of return RedirectToAction("CreateBoard"); you alway can write like this:

IEnumerable<BMModel> searchModel = new List<BMModel>();
searchModel.Add(new BMModel
{
 ... // Here you should init your model as you like
});
searchModel.Add(new BMModel
{
 ... // Here you should init your model as you like
});
//And so on
return CreateBoard(IEnumerable<BMModel> search)

I just don't understand from where you whould like to get your model. But hope you get the idea.

Answer 2

Instead of response.redirect, can you try

return this.view("CreateBoard",q);

this may work

Answer 3

You cannot pass a collection of objects to a GET method. The RedirectToAction() method will use the .ToString() method of the object(s) your passing as route parameters to generate the query string. In your case, your object is List<BMModel> which means that it is passing search = "System.Collection.Generic.List<yourAssembly.BMModel>" which cannot be bound to your parameter. Fortunately this does not work because it it did it would easily exceed the query string limit and throw an exception.

Remove the POST method and change the GET method to include the 3 parameters you want to post.

[HttpGet]
public ActionResult CreateBoard(int BMNo, DateTime BMDate, string MPlace)
{
  ViewData["Boards"] = // Generate and filter your query here based on the parameters
  return View()
}

and change the your form to FormMethod.Get

@using (Html.BeginForm("CreateBoard", "yourControllerName", FormMethod.Get))
{
    ....
}

Note you view currently shows a number of controls which seem unrelated to you search query so it unclear what these are for.

I recommend you consider using ajax to post the values to a separate controller method that returns a partial view containing the html table to avoid need to refresh the whole page each time.