Implement and populate view model db first - asp.net-mvc

Question

I have created a page were the user searches for a book and the book details are loaded using partial view. I have successfully done this.
The action method in the controller used to do this:
[HttpGet]
public ActionResult LoanSearch(string q)
{
var loans = GetLoans(q);
return PartialView(loans);
}
private List<Loan> GetLoans(string searchString)
{
return db.Loans
.Where(a => a.Book.Name.Contains(searchString))
.ToList();
}
As you can see the LoanSearch action method is decorated with HTTPGET.
The View for this:
#using (Html.BeginForm())
{
foreach (var item in Model)
{
<ul>
<li>#item.ISBN</li>
<li>#item.Book.Name</li>
<li>#item.Book.Author</li>
<li> #item.FinePrice</li>
</ul>
#Html.ActionLink("Return Book", "LoanSearch", new { id = item.LoanId });
}
}
What I would like to do is update the finePrice in loans db and change onLoan from 1 to 0 in the books db. This should happen when the user clicks on the above Html.ActionLink above.
To achieve this I created the following HTTPPOST action method and also used a view model as I needed to update 2 tables (Loan,Book) at the same time.(is a view model needed?)
[HttpPost]
public ActionResult LoanSearch(BookReturnVM model, string searchString)
{
var bookquery = db.Loans.Where(a => a.Book.Name.Contains(searchString));
var loanquery = db.Loans.Where(a => a.Book.Name == model.BookTitle);
var finePrice = db.Loans.Where(g => g.FinePrice == model.FinePrice);
BookReturnVM model1 = new BookReturnVM
{
OnLoan = model.OnLoan,
FinePrice = model.FinePrice,
};
if (ModelState.IsValid)
{
var fine = db.Loans.FirstOrDefault(g => g.FinePrice == model.FinePrice);
var bookLoan = db.Loans.FirstOrDefault(a => a.Book.Name.Contains(searchString));
if (bookLoan != null)
{ //changes the onloan status to 1 which makes it 'on loan'
bookLoan.Book.OnLoan = 0;
};
db.Entry(bookLoan).State = EntityState.Modified;
db.SaveChanges();
}
return View();
I would like the finePrice found in the Loan table to be updated based on the calculation below. The finePrice calculation is done in the Loan model:
private decimal? _FinePrice;
public decimal? FinePrice
{
get
{
if(DateTime.Now>CheckOutDate)
{
this._FinePrice= ((DateTime.Now - CheckOutDate).Days)*0.50M;
}
else
{
this._FinePrice = 0M;
}
return this._FinePrice;
}
set
{
this._FinePrice = value;
}
}
In conclusion when I search for a book, the details of the book appears(in partial view,which it does), and when I click a button(on the same partial view page) the OnLoan (book table) changes from 1 to 0 and the finePrice (loan table)is updated for that particular book.
I assume the problem lies within the HTTP POST action method but do not know how to solve this in order to solve the above question.
Thanks for your time

Answer 1

You can do something like this:
Tables:
USE [Breaz]
GO
/****** Object: Table [dbo].[Loan] Script Date: 6/26/2017 11:15:15 AM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
CREATE TABLE [dbo].[Loan](
[LoanId] [int] IDENTITY(1,1) NOT NULL,
[ISBN] [varchar](20) NULL,
[Name] [varchar](20) NULL,
[Author] [varchar](20) NULL,
[FinePrice] [money] NOT NULL,
CONSTRAINT [PK_Loan] PRIMARY KEY CLUSTERED
(
[LoanId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
SET ANSI_PADDING OFF
GO
Controller
public class HomeController : Controller
{
[HttpGet]
public PartialViewResult LoanSearchByIdAndUpdate(int id)
{
//DO your database update here
//I will change the find to 2.37
Loan loan = new Loan();
var bookName = String.Empty;
using (BreazEntities26 db = new BreazEntities26())
{
loan = db.Loans.Find(id);
loan.FinePrice = 2.37M;
bookName = loan.Name;
}
IList<Loan> loans = new List<Loan>();
loans.Add(loan);
return PartialView("_LoanSearch", loans););
}
[HttpGet]
public PartialViewResult LoanSearch(string q)
{
var loans = GetLoans(q);
return PartialView("_LoanSearch", loans););
}
private List<Loan> GetLoans(string searchString)
{
using (BreazEntities26 db = new BreazEntities26())
{
return db.Loans
.Where(a => a.Name.Contains(searchString))
.ToList();
}
}
IndexValid2.cshtml
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width" />
<title>IndexValid2</title>
<script src="~/Scripts/jquery-1.12.4.min.js"></script>
#*MAKE SURE to put the next script in*#
<script src="~/Scripts/jquery.unobtrusive-ajax.min.js"></script>
<script type="text/javascript">
$(function () {
$('#passSearchValue').click(function () {
var searchValue = $('#q').val();
this.href = this.href + '?q=' + encodeURIComponent(searchValue);
});
})
</script>
</head>
<body>
<div>
Search for book:
#Html.TextBox("q", null, new { id = "q" })
#*https://stackoverflow.com/questions/5838273/actionlink-routevalue-from-a-textbox*#
#Ajax.ActionLink(
"Search",
"LoanSearch",
null,
new AjaxOptions
{
UpdateTargetId = "result",
InsertionMode = InsertionMode.Replace,
HttpMethod = "GET"
},
new { id = "passSearchValue" })
</div>
<div id="result"></div>
</body>
</html>
partial view in shared, _LoanSearch.cshtml
#model IEnumerable<Testy20161006.Models.Loan>
#foreach (var item in Model)
{
<ul>
<li>#item.ISBN</li>
<li>#item.Name</li>
<li>#item.Author</li>
<li> #item.FinePrice</li>
</ul>
#Html.ActionLink("Update", "LoanSearchByIdAndUpdate", new { id = item.LoanId });
<p />
#Html.ActionLink("Return to Search", "IndexValid2");
}