Dynamically adding items into view and posting back to controller (ASP.NET MVC 4)

Question

I have a ASP.NET MVC 4 app with model, that contains and colection (IEnumerable or IList), i.e.:

class MyModel
{
  pu         


        

Answer 1

I did this with help of Backbone (for file uploader) where i insert template whenever user click #addButton View:

@using Telerik.Web.Mvc.UI
@{
    ViewBag.Title = "FileUpload";
    Layout = "~/Areas/Administration/Views/Shared/_AdminLayout.cshtml";
}
<div id="fileViewContainer" class="span12">
<h2>File upload</h2>
@foreach(var fol in (List<string>)ViewBag.Folders){
        <span style="cursor: pointer;" class="uploadPath">@fol</span><br/>
    }
    @using (Html.BeginForm("FileUpload", "CentralAdmin", new { id = "FileUpload" }, FormMethod.Post, new { enctype = "multipart/form-data" }))
    {
        <label for="file1">Path:</label>
        <input type="text" style="width:400px;" name="destinacionPath" id="destinacionPath"/><br />
        <div id="fileUploadContainer">
            <input type="button" class="addButton" id="addUpload" value="Add file"/>
            <input type="button" class="removeButton" id="removeUpload" value="Remove file"/>
        </div>

        <input type="submit" value="Upload" />
    }
</div>
<script type="text/template" id="uploadTMP">
     <p class="uploadp"><label for="file1">Filename:</label>
     <input type="file" name="files" id="files"/></p>
</script>
@{
    Html.Telerik().ScriptRegistrar().Scripts(c => c.Add("FileUploadInit.js"));
}

FileUploadInit.js

$(document).ready(function () {
    var appInit = new AppInit;
    Backbone.history.start();
});
window.FileUploadView = Backbone.View.extend({
    initialize: function () {
        _.bindAll(this, 'render', 'addUpload', 'removeUpload', 'selectPath');
        this.render();
    },
    render: function () {
        var tmp = _.template($("#uploadTMP").html(), {});
        $('#fileUploadContainer').prepend(tmp);
        return this;
    },
    events: {
        'click .addButton': 'addUpload',
        'click .removeButton': 'removeUpload',
        'click .uploadPath': 'selectPath'
    },
    addUpload: function (event) {
        this.render();
    },
    removeUpload: function (event) {
        $($('.uploadp')[0]).remove();
    },
    selectPath: function (event) {
        $('#destinacionPath').val($(event.target).html());
    }
});
var AppInit = Backbone.Router.extend({
    routes: {
        "": "defaultRoute"
    },
    defaultRoute: function (actions) {
        var fileView = new FileUploadView({ el: $("#fileViewContainer") });
    }
});

In Controller you keep your code

I Hope this will help.

Answer 2

At the end I did similar stuff what STO was suggesting, but with the custom (non-linear) indices for collections suggested by Phil Haack.

This uses manual naming of elements (so I'm not binding directly to the model) and I can use custom instances (for empty element templates). I've also created some helper methods to generate me the code for the instance, so it's easier to generate code for actual instances from the model or empty ones.

Answer 3

I'm not sure what do you mean 'collection variable names' and probably my solution is kind of magic you noticed.

My solution is based on copying existing editor for element and altering input names via Javascript.

First of all, we need to mark up our editor. This is a code of form outputs editor for collection

        @for (var i = 0; i < Model.Count; i++)
        {
            <div class="contact-card">
                @Html.LabelFor(c => Model[i].FirstName, "First Name")
                @Html.TextBoxFor(c => Model[i].FirstName)
                <br />
                @Html.LabelFor(c => Model[i].LastName, "Last Name")
                @Html.TextBoxFor(c => Model[i].LastName)
                <br />
                @Html.LabelFor(c => Model[i].Email, "Email")
                @Html.TextBoxFor(c => Model[i].Email)
                <br />
                @Html.LabelFor(c => Model[i].Phone, "Phone")
                @Html.TextBoxFor(c => Model[i].Phone)
                <hr />
            </div>

        }

Our editor is placed into div with class contact-card. On rendering, ASP.NET MVC gives names like [0].FirstName, [0].LastName ... [22].FirstName, [22].LastName to inputs used as property editors. On submitting Model Binder converts this to collection of entities based both on indexes and property names.

Next we create javascript function that copies last editor and increases index in brackets by 1. On submitting it adds additional element to collection:

var lastContent = $("#contact-form .contact-card").last().clone();
$("#contact-form .contact-card").last().after(lastContent);

$("#contact-form .contact-card")
    .last()
    .find("input")
    .each(function () {
        var currentName = $(this).attr("name");
        var regex = /\[([0-9])\]/;
        var newName = currentName.replace(regex, '[' + (parseInt(currentName.match(regex)[1]) + 1) + ']');
        $(this).val('');
        $(this).attr('name', newName);
    });

VOILA!! On submitting we will get one more element!