Using selected dropdownlist value in query - asp.net-mvc

Question

I am trying to insert data into a sql server temporary table based on a value picked from a dropdownlist. In my model I have 4 classes:
public class Customer
{
[Key]
public int CustID { get; set; }
public string CustName { get; set; }
public virtual ICollection<Sale> Sales { get; set; }
}
}
public class Product
{
[Key]
public int ProductID { get; set; }
public string ProductName { get; set; }
public decimal Price { get; set; }
public virtual ICollection<Sale> Sales { get; set; }
}
}
public class Sale
{
[Key]
public int RecordID { get; set; }
public int ProductID { get; set; }
public int CustID { get; set; }
public int InvoiceNo { get; set; }
public int Quantity { get; set; }
public virtual Customer Customer { get; set; }
public virtual Product Product { get; set; }
}
public class TempTable
{
[Key]
public int recordID { get; set; }
public string CustName { get; set; }
public string PoductName { get; set; }
public decimal Price { get; set; }
public int Quantity { get; set; }
public int InvoiceNo { get; set; }
}
In my SaleController I have the following action:
public ActionResult OldInvoice(Sale sale)
{
ViewBag.InvoiceNo = new SelectList(db.Sales, "RecordID", "InvoiceNo", sale.RecordID);
return View();
}
[HttpPost]
public ActionResult OldInvoice(TempTable t, int InvoiceNoToSearch = 0)
{
var query = (from s in db.Sales
join c in db.Customers on s.CustID equals c.CustID
join p in db.Products on s.ProductID equals p.ProductID
where s.InvoiceNo.Equals(s.InvoiceNo == InvoiceNoToSearch)
select new
{
s.InvoiceNo,
s.Quantity,
c.CustName,
p.ProductName,
p.Price
}).ToList();
foreach (var temp in query)
{
t.CustName = temp.CustName;
t.InvoiceNo = temp.InvoiceNo;
t.PoductName = temp.ProductName;
t.Price = temp.Price;
t.Quantity = temp.Quantity;
db.TempTables.Add(t);
db.SaveChanges();
}
return RedirectToAction("OldInvoice");
}
and finally my view is:
#model IEnumerable<UsingDropDownListValueInQuery.Models.Sale>
#{
ViewBag.Title = "OldInvoice";
}
<h2>OldInvoice</h2>
#using (Html.BeginForm()) {
#Html.AntiForgeryToken()
#Html.ValidationSummary(true)
#Html.DropDownList("InvoiceNo")
<p>
<input type="submit" value="Save" />
</p>
}
I get the following error:
Unable to cast the type 'System.Boolean' to type 'System.Object'. LINQ to Entities only supports casting EDM primitive or enumeration types.
If I enter in the Where Statement an Existing InvoiceNo it does the job but not if I try to pick the value from the dropdownlist

Answer 1

The problem seems to be that you're never actually sending the value back. In your view, you've created a select named "InvoiceNo", but in your post action, you don't have any parameters that can accept that value. The closest and probably the one you intend to bind to is InvoiceNoToSearch, but if that's the variable you want to use, your view needs to match:
#Html.DropDownList("InvoiceNoToSearch")
Of course, that means your SelectList in ViewBag no longer binds automatically as the options for that select, but that can be fixed by just explicitly specifying it:
#Html.DropDownList("InvoiceNoToSearch", (SelectList)ViewBag.InvoiceNo)