Add a New Item to the Database
In this section, you will add the ability for users to create a new book. In app.js, add the following code to the view model:
self.authors = ko.observableArray();
self.newBook = {
Author: ko.observable(),
Genre: ko.observable(),
Price: ko.observable(),
Title: ko.observable(),
Year: ko.observable()
}
var authorsUri = '/api/authors/';
function getAuthors() {
ajaxHelper(authorsUri, 'GET').done(function (data) {
self.authors(data);
});
}
self.addBook = function (formElement) {
var book = {
AuthorId: self.newBook.Author().Id,
Genre: self.newBook.Genre(),
Price: self.newBook.Price(),
Title: self.newBook.Title(),
Year: self.newBook.Year()
};
ajaxHelper(booksUri, 'POST', book).done(function (item) {
self.books.push(item);
});
}
getAuthors();
In Index.cshtml, replace the following markup:
<div class="col-md-4">
<!-- TODO: Add new book -->
</div>
With:
<div class="col-md-4">
<div class="panel panel-default">
<div class="panel-heading">
<h2 class="panel-title">Add Book</h2>
</div>
<div class="panel-body">
<form class="form-horizontal" data-bind="submit: addBook">
<div class="form-group">
<label for="inputAuthor" class="col-sm-2 control-label">Author</label>
<div class="col-sm-10">
<select data-bind="options:authors, optionsText: 'Name', value: newBook.Author"></select>
</div>
</div>
<div class="form-group" data-bind="with: newBook">
<label for="inputTitle" class="col-sm-2 control-label">Title</label>
<div class="col-sm-10">
<input type="text" class="form-control" id="inputTitle" data-bind="value:Title"/>
</div>
<label for="inputYear" class="col-sm-2 control-label">Year</label>
<div class="col-sm-10">
<input type="number" class="form-control" id="inputYear" data-bind="value:Year"/>
</div>
<label for="inputGenre" class="col-sm-2 control-label">Genre</label>
<div class="col-sm-10">
<input type="text" class="form-control" id="inputGenre" data-bind="value:Genre"/>
</div>
<label for="inputPrice" class="col-sm-2 control-label">Price</label>
<div class="col-sm-10">
<input type="number" step="any" class="form-control" id="inputPrice" data-bind="value:Price"/>
</div>
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>
</div>
</div>
</div>
This markup creates a form for submitting a new author. The values for the author drop-down list are data-bound to the authors
observable in the view model. For the other form inputs, the values are data-bound to the newBook
property of the view model.
The submit handler on the form is bound to the addBook
function:
<form class="form-horizontal" data-bind="submit: addBook">
The addBook
function reads the current values of the data-bound form inputs to create a JSON object. Then it POSTs the JSON object to /api/books
.