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POHow to map a model with reference to a list of another model in EntityFramework Code First
 

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  1. POHow to map a model with reference to a list of another model in EntityFramework Code First
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    <p>I have a project in which I am using EntityFramework Code First to manage the database. The models I'm using for this are as follows:</p> <pre><code>[Table("Data")] public class Data { [Key, Column("Id")] public int Id { get; set; } [Column("Code")] public string Code { get; set; } [Column("Name")] public string Name { get; set; } [Column("Description")] public string Description { get; set; } public virtual List&lt;DataAttribute&gt; Attributes { get; set; } } </code></pre> <p>and</p> <pre><code>[Table("DataAttribute")] public class DataAttribute { [Key, Column("Id")] public int Id { get; set; } [Column("IdData"), ForeignKey("Data")] public int IdData { get; set; } [Column("Name")] public string Name { get; set; } [Column("Description")] public string Description { get; set; } public virtual Data Data { get; set; } } </code></pre> <p>The issue I'm having with this is when I try to edit a Data object (along with its related DataAttribute values). I haven't gotten it to map correctly when submitting a form with both the Data elements and the DataAttribute elements. I give an example of .cshtml file.</p> <pre><code>@model MVCTestApp.Models.Data @{ ViewBag.Title = "Edit"; } @section Scripts { &lt;script type="text/javascript"&gt; $(function () { $('#new-row').click(function () { $('table tbody').append( '&lt;tr&gt;' + '&lt;td&gt;&lt;input class="name" type="text" /&gt;&lt;/td&gt;' + '&lt;td&gt;&lt;input class="description" type="text" /&gt;&lt;/td&gt;' + '&lt;td&gt;&lt;a class="delete" href="#"&gt;Delete&lt;/a&gt;&lt;/td&gt;' + '&lt;/tr&gt;' ); $('.delete').click(function () { $(this).parent().parent().remove(); }); }); }); &lt;/script&gt; } @using (@Html.BeginForm("Edit", "Data", FormMethod.Post)) { @Html.HiddenFor(a =&gt; a.Id) Name: &lt;br /&gt; @Html.TextBoxFor(a =&gt; a.Name) &lt;br /&gt; Description: &lt;br /&gt; @Html.TextBoxFor(a =&gt; a.Description) &lt;br /&gt; Code: &lt;br /&gt; @Html.TextBoxFor(a =&gt; a.Code) &lt;br /&gt; &lt;table&gt; &lt;thead&gt; &lt;tr&gt; &lt;th&gt; Name &lt;/th&gt; &lt;th&gt; Description &lt;/th&gt; &lt;th&gt; &lt;/th&gt; &lt;/tr&gt; &lt;/thead&gt; &lt;tbody&gt; &lt;tr&gt; &lt;td&gt; &lt;a id="new-row" href="#"&gt;New Row&lt;/a&gt; &lt;/td&gt; &lt;td colspan="2"&gt; &lt;/td&gt; &lt;/tr&gt; @if (Model != null) { foreach (var item in Model.Attributes) { &lt;tr&gt; @Html.HiddenFor(b =&gt; item.Id) @Html.HiddenFor(b =&gt; item.IdData) &lt;td class="name"&gt;@Html.TextBoxFor(b =&gt; item.Name) &lt;/td&gt; &lt;td class="description"&gt;@Html.TextBoxFor(b =&gt; item.Description) &lt;/td&gt; &lt;td&gt; &lt;a class="delete" href="#"&gt;Delete&lt;/a&gt; &lt;/td&gt; &lt;/tr&gt; } } &lt;/tbody&gt; &lt;/table&gt; &lt;input type="submit" value="submit" /&gt; } </code></pre> <p>The question is this. </p> <p><strong>How can I make EntityFramework recognize the list of DataAttributes on the Controller when posting?</strong></p> <p>Here's the code I'm using right now.</p> <pre><code> [HttpPost] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(Data model) { if (model != null) { db.Data.Add(model); //model has the model.Attributes list set as null db.SaveChanges(); return View("Index", db.Data.OrderBy(a =&gt; a.Id).ToList()); } return View(); } </code></pre> <p>Thank you in advance.</p>
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    1. UStriangulito
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    1. COyou need to ensure serialization of the list when you send it back to the controller. You could also try setting up a specific ViewModel that is returned that contains the list.
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      1. POHow to map a model with reference to a list of another model in EntityFramework Code First
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    2. COHow would I serialize it?, by making it a json object or something like that and then passing it to the controller?
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    3. COThat could easily work, What I would do is add an argument to the ActionResult and set it to string and use the built in json parser to get the values and set the models attributes. you could use JSON on the client to serialize the object to be sent back.
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