Question

I am really struggling with getting two tables I have joined to show in a view (I just want to show the customer name which comes from the customer tables and the bill status from the bill table – both of which are joint on a CustomerId primary key). I spent ages researching this and came to the conclusion of creating another model just for this view which I did however in my controller when I try and use the following:

Function ShowAll() As ViewResult
    Dim BillQuery = From d In db.Bills
                    Join c In db.Customers On d.CustomerId Equals c.CustomerId
                    Select c.CustSurname, d.BillStatus

    Dim BillList As List(Of BillView) = BillQuery.ToList()

    Return View(BillList)
End Function

I get an error:

Value of type ‘System.Collections.Generic.List(Of )’ cannot be converted to ‘System.Collections.Generic.List(Of Laundry.BillView)’

Here are my Bill and BillView models:

Imports System.Data.Entity
Imports System.ComponentModel.DataAnnotations

Public Class Bill

    'Key
    Public Property BillId() As Integer

    'Others
    <Required()>
    <Display(Name:="Customer ID")>
    Public Property CustomerId() As String

    <Required()>
    <Display(Name:="Bill Status")>
    Public Property BillStatus() As String

End Class

Public Class BillView

    Public Property CustSurname() As String

    Public Property BillStatus() As String

End Class

And Customer Model:

Imports System.Data.Entity
Imports System.ComponentModel.DataAnnotations

Public Class Customer

'Key
Public Property CustomerId() As Integer

'Others
<Display(Name:="Group ID")>
Public Property GroupId() As Integer

<Required()>
<Display(Name:="Firstname")>
Public Property CustFirstname() As String

<Required()>
<Display(Name:="Surname")>
Public Property CustSurname() As String

<Display(Name:="Email")>
Public Property CustEmail() As String

<Display(Name:="Cellphone")>
Public Property CustCellphone() As String

<Display(Name:="Address")>
Public Property CustAddress() As String

<Required()>
<Display(Name:="Status")>
Public Property CustStatus() As String

<Required()>
<Display(Name:="Account Balance")>
Public Property AccBalance() As Double

<Required()>
<Display(Name:="Loyalty Ammount")>
Public Property LoyaltyAmount() As Double

<Required()>
<Display(Name:="Customer Discount")>
Public Property PersonalDiscount() As Double


End Class

Answer 1

It looks like your first LINQ query is returning an anonymous type which can’t then be cast to List(Of BillView). Try the following code to return a collection of BillView models prior to the cast (note the added syntax Select New BillView With {}).

Function ShowAll() As ViewResult
    Dim BillQuery = From d In db.Bills
                    Join c In db.Customers On d.CustomerId Equals c.CustomerId
                    Select New BillView With {.CustSurname = c.CustSurname, .BillStatus =  d.BillStatus}

    Dim BillList As List(Of BillView) = BillQuery.ToList()

    Return View(BillList)
End Function