MVC4: Model's properties are null - 2

Question

For some reason, when I press any of the buttons of my view, all properties of the model passed to the action method are null:

View:

@using (Html.BeginForm("FolderChange", "EdiSender", FormMethod.Post, new {id = "ediFilesForm"}))
{
    var directoriesSelectList = new SelectList(Model.Directories);
    @Html.DropDownListFor(m => m.SelectedDirectory, directoriesSelectList, new {@Id = "Directories", @style = "width:Auto;", @size = 20, onchange = "$('#ediFilesForm').submit()", name = "action:FolderChange"})

    var ediFilesSelectList = new SelectList(Model.EdiFileNames);
    @Html.DropDownListFor(m => m.SelectedEdiFile, ediFilesSelectList, new {@Id = "EdiFileNames", @style = "width:Auto;", @size = 20})
}

<br/>
...

<form action="" method="post">
    <input type="submit" value="Send" name="action:Send" />
    <input type="submit" value="Delete" name="action:Delete" />
    <input type="submit" value="Refresh" name="action:Refresh" />
</form>

Controller:

    [HttpPost]
    [MultipleButton(Name = "action", Argument = "Send")]
    public ActionResult Send(EdiFileModel ediFileModel)
    {
           ....
    }

    [AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
public class MultipleButtonAttribute : ActionNameSelectorAttribute
{
    public string Name { get; set; }
    public string Argument { get; set; }

    public override bool IsValidName(ControllerContext controllerContext, string actionName, MethodInfo methodInfo)
    {
        var isValidName = false;
        var keyValue = string.Format("{0}:{1}", Name, Argument);
        var value = controllerContext.Controller.ValueProvider.GetValue(keyValue);

        if (value != null)
        {
            controllerContext.Controller.ControllerContext.RouteData.Values[Name] = Argument;
            isValidName = true;
        }

        return isValidName;
    }
}

It used to work when my buttons were within the Html.BeginForm() block, but I cannot have it like that anymore, because it has now action name as FolderChange(), which is different from e.g. Send() or other action method that handles button press.

Thanks.

EDITED:

@section scripts
{
    <sctipt type="text/javascript">
    $("#Directories").change(function () {
        var selectedDirectory = $("#Directories").val();   

        $(function () {
            $.getJSON('/DoWork/FolderChangeAjaxCall?selectedDirectory=' + selectedDirectory, function (result) {
                var ddl = $('#EdiFileNames');
                ddl.empty();
                $(result).each(function () {
                    $(document.createElement('option'))
                .attr('value', this.Id)
                .text(this.Value)
                .appendTo(ddl);
                });
            });
        });
    });    
    </sctipt>
}

<h2>Existing EDI Files</h2>
@using (Html.BeginForm("FolderChange", "EdiSender", FormMethod.Post, new {id = "ediFilesForm"}))
{
    var directoriesSelectList = new SelectList(Model.Directories);
    @Html.DropDownListFor(m => m.SelectedDirectory, directoriesSelectList, new {@Id = "Directories", @style = "width:Auto;", @size = 20})

    var ediFilesSelectList = new SelectList(Model.EdiFileNames);
    @Html.DropDownListFor(m => m.SelectedEdiFile, ediFilesSelectList, new {@Id = "EdiFileNames", @style = "width:Auto;", @size = 20})

Answer 1

Here it is, it's probably way off from what you thought the answer would be, but it will cascade the dropdowns. Your going to have to substitute your values and context in, but it will work. Now you can place your buttons in the form and not have to have the dropdown's submit the form, which is pretty poor design anyways.

@Html.DropDownListFor(x => x.ddlID, Model.myDDLList, new { id = "ddl" }) 

@Html.DropDownListFor(x => x.myDDLList2, Model.myDDLList2, new { id = "foo" }) 

Script

$("#ddl").change(function () {

        var Id = $("#ddl").val(); //1st dropdown Value        

        $(function () {
            $.getJSON('/DoWork/AjaxCall?Id=' + Id, function (result) {
                var ddl = $('#foo');
                ddl.empty();
                $(result).each(function () {
                    $(document.createElement('option'))
                .attr('value', this.Field1)
                .text(this.Field2)
                .appendTo(ddl);
                });
            });
        });
    });

Controller

public ActionResult AjaxCall(int Id)
    {
        using (PerformanceEntities context = new PerformanceEntities())
        {             
            return this.Json(
                  (from obj in context.ACCOUNT.Where(x => x.ACCT_ID == Id).ToList() 
                   select new
                   { 
                       Field1 = obj.ACCT_ID,
                       Field2 = obj.ACCT_NAME 
                   }),
                  JsonRequestBehavior.AllowGet
               );
        }         
    }

You can check out this post for reference