How to realize Edit method with 2 models in 1 View

Question

The beginning of my topic is here.

Using DropDownList dont allow me to edit Author`s name.. But that solution is really good.

I need to edit all 4 fields like name, title, year and price.

I try to make something like composite model:

public class BookAuthorCompositeModel
{
    public Author author { get; set; }
    public Book book { get; set; }
}

Change my get method:

// GET: Books/Edit/5       
public ActionResult Edit(int? id)
{
    if (id == null)
    {
        return HttpNotFound();
    }
    var compModel = new BookAuthorCompositeModel();
    compModel.book = dbBooks.Books.ToList().Where(a => a.Id == id).SingleOrDefault();
    compModel.author = dbBooks.Authors.ToList().Where(x => x.Id == id).SingleOrDefault();
    return View(bookEdit);
}

and it displays all I need (i tap "edit" and see information about name, title, year and price).

My view is:

@model BookStorage.Models.BookAuthorCompositeModel

@{
    ViewBag.Title = "Edit";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>Edit</h2>

@using (Html.BeginForm())
{
    @Html.AntiForgeryToken()

    <div class="form-horizontal">
        <h4>Book</h4>
        <hr />
        @Html.ValidationSummary(true, "", new { @class = "text-danger" })
        @Html.HiddenFor(model => model.book.Id)

        <div class="form-group">
            @Html.LabelFor(model => model.author.AuthorName, "AuthorName", htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.author.AuthorName, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.author.AuthorName, "", new { @class = "text-danger" })
            </div>
        </div>
        <div class="form-group">
            @Html.LabelFor(model => model.book.Title, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.book.Title, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.book.Title, "", new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.book.YearPublish, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.book.YearPublish, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.book.YearPublish, "", new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.book.Price, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.book.Price, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.book.Price, "", new { @class = "text-danger" })
            </div>
        </div>


        <div class="form-group">
            <div class="col-md-offset-2 col-md-10">
                <input type="submit" value="Save" class="btn btn-default" />
            </div>
        </div>
    </div>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

but something wrong is in Post method:

[HttpPost]
public ActionResult Edit(Book book)
{
    if (ModelState.IsValid)
    {
        dbBooks.Entry(BAmodel.book).State = EntityState.Modified;
        dbBooks.Entry(BAmodel.author).State = EntityState.Modified;

        dbBooks.SaveChanges();
        return RedirectToAction("Index");
    }
    return View(book);
}

dbBooks.SaveChanges(); leads to error (Store update, insert, or delete statement affected an unexpected number of rows (0).). I think using this kind of ViewModel helps to edit all rows, but it doesn't send data to DB, and I can't understand what is wrong.

Answer 1

If I understood correctly, what you want is to update a context "Book" and a context "Author" at the same API method.

To do so, first I would make a ViewModel that contains both objects, which you already have:

public class BookAuthorCompositeModel
{
    public Author author { get; set; }
    public Book book { get; set; }
}

(This can be modified for validation purposes, maybe creating new objects for validation. At least, I did it like that. But let's go on.)

Now, you need to receive that same ViewModel on your API call, and then do what you need with the objects. To do so, I usually do a Get call on my context, obtaining the object to be modified. Then I'm free to update my context:

[HttpPost]
    public ActionResult Edit(BookAuthorCompositeModel model)
    {
        ...
    }

To get the object to be modified, depends on what you are using. Simple repository pattern, Unit pattern, doesn't matter. When you get the Book entry, just modify it, use Update function, which I belive to be dbBooks.BookContext.Update(book), where "book" is variable. Something like this:

var book = dbBooks.BooksContext.Get(model.Book.BookId);

book.name = "New Name";

dbBooks.BooksContext.Update(book);
dbBooks.SaveChanges();

The method for getting and updating ( .Get() and .Update() ) must be the ones from the pattern that you are using, but maybe this can help you.

Good luck!