Question

EDITED: I am retrieving some order data and am trying to grab the product description from another table using the productID from the first table. The code below works fine but I need to query the products table using the productid to get the string,product description

 Dim result = From c In ctx.orders
                         Where c.CustomerId = 13
                Select New With
                {c.OrderDate,
                 c.PurchaseOrderNumber,
                 c.ProductId,
                 c.ProductPrice,
                 c.ProductQty}

I tried the suggestions below and get a “field or property named productid doesnt exist” error
using this method

 Dim result = From c In ctx.orders
                         Where c.CustomerId = 13
                  Join prod In ctx.products on c.ProductId Equals prod.Id
                Select New With
                {c.OrderDate,
                 c.PurchaseOrderNumber,
                 prod.Description,
                 c.ProductPrice,
                 c.ProductQty}

Answer 1

Why not use the join operator C# version and join operator VB version

Dim result = From c In ctx.orders
             Join prod In ctx.products On c.ProductId Equals prod.Id
             Where c.CustomerId = custid
             Select New With
                    {c.OrderDate,
                      prod.Description
                     c.ProductPrice,
                     c.ProductQty}

I made a sample class to test the join and this worked perfectly. Are you sure it loaded the products tables and it has the property?

Module Module1

Sub Main()
    Dim ctx As List(Of X) = New List(Of X)
    Dim x1 As X = New X()
    x1.One = 1
    x1.Two = 2
    Dim x2 As X = New X()
    x2.One = 10
    x2.Two = 20
    ctx.Add(x1)
    ctx.Add(x2)

    Dim ctx2 As List(Of Y) = New List(Of Y)
    Dim y1 As Y = New Y()
    y1.Three = 1
    y1.Four = 2
    Dim y2 As Y = New Y()
    y2.Three = 10
    y2.Four = 20
    ctx2.Add(y1)
    ctx2.Add(y2)

    Dim result = From c In ctx
         Join prod In ctx2 On c.One Equals prod.Three
         Where c.One = 1
         Select New With
                {c.One,
                 prod.Four,
                 c.Two}

    For Each a In result
        Console.Beep()
    Next

    Console.Read()
End Sub

Class X
    Public Property One As Integer
    Public Property Two As Integer
End Class

Class Y
    Public Property Three As Integer
    Public Property Four As Integer
End Class

End Module