Question

I have a page where you can edit a client. On this page, you can also upload files for a client. You click a button, a jQuery dialog opens, you upload a file, and click Save.

Here’s my /Clients/Edit view:

<script type="text/javascript" language="javascript">

    $(document).ready(function () {

        // add file click event
        $("a#addFile").click(function () {
            $.ajax({
                url: '@Url.Content("/ClientFiles/Create/")' + @Model.ClientId,
                context: document.body,
                success: function (data) {
                    // open dialog with Create partial view data
                    $("#dialog-add").html(data).dialog("open");
                }
            });

            return false;
        });


        // add file dialog settings
        $("#dialog-add").dialog({
            modal: true,
            buttons: {
                "Save": function () {
                    $.validator.unobtrusive.parse("#AddFileForm");
                    if ($("#AddFileForm").valid()) {
                        $.post("/ClientFiles/Create", $("#AddFileForm").serialize(),
                            function (data) {
                                $("#dialog-add").dialog("close");   // close dialog
                            });
                    }
                }
            }
        });
    });

</script>

@using (Html.BeginForm("Edit", "Clients", FormMethod.Post))
{
    @Html.HiddenFor(m => m.ClientId)            

    <a id="addFile">Add a new file</a>
    <div id="dialog-add" title="" style="display:none"></div>        

    <input type="submit" value="Save" />            
}

Here is my /ClientFiles/Create partial view:

@model Models.ClientFileViewModel

@using (Html.BeginForm("Create", "ClientFiles", FormMethod.Post, new { @id = "AddFileForm", enctype = "multipart/form-data" }))
{
    @Html.ValidationSummary(true)

    @Html.HiddenFor(model => model.ClientId)    
    @Html.TextBoxFor(model => model.ModelFile, new { type = "file" })

    @Html.ValidationSummary()
}

Here’s my ClientFileViewModel:

public class ClientFileViewModel
{
    [ScaffoldColumn(false)]
    public int ClientFileId { get; set; }

    public int ClientId { get; set; }
    public HttpPostedFile ModelFile { get; set; }
}

And finally, my ClientFilesController methods:

public ActionResult Create(int id)
{
    return PartialView(new ClientFileViewModel { ClientId = id  } );
}

public JsonResult Create(ClientFileViewModel viewModel)
{
    if (ModelState.IsValid)
    {
        if (viewModel.ModelFile != null)
        {
            // upload file here
        }
    }

    return Json(new { success = true });
}

So everything works up until I post to Create(ClientFileViewModel viewModel). When I go through the debugger, the view model contains ClientId, but ModelFile is null.

Am I doing something wrong that is causing the file to not be passed with the view model?

Answer 1

You should use the base class (HttpPostedFileBase), i.e. replace:

public HttpPostedFile ModelFile { get; set; }

with:

public HttpPostedFileBase ModelFile { get; set; }

in your view model.

---

This being said, that’s only half of your issues. You seem to be using an AJAX request to submit the form:

$.post("/ClientFiles/Create", $("#AddFileForm").serialize(),

You cannot use AJAX to upload files to the server. You could use some plugin such as jquery.form which supports file input fields and generates a hidden iframe to circumvent this limitation. So if you decide to use the plugin you could do the following to AJAXify it:

"Save": function () {
    $.validator.unobtrusive.parse("#AddFileForm");
    if ($("#AddFileForm").valid()) {
        $("#AddFileForm").ajaxSubmit(function() {
            $("#dialog-add").dialog("close");
        });
    }
}

Other popular plugins that allow you to upload files are Uploadify, Blueimp File Upload, Ajax Upload, …