LINQ query is not working - vb.net

Question

I am trying to create a dictionary from a list. I am trying to filter the list such that it contains the id that I am adding as a key to the dictionary. So dictionary would be Key, List - with id as Key.
I have no idea why the following won't work - although the rawlist contains ids, filteredlist is empty. I am checking the value within the loop. Fresh set of eyes please?
resultList is dictionary(string, List)
For Each c As String In listIds
Dim filteredlist = rawList.Where(Function(x) x.id.Trim().Contains(c.Trim())).ToList()
resultList.Add(c,filteredlist)
Next
I need the filtered list. I have tried Contains, Equals and "="
i.e.
Dim filteredlist = rawList.Where(Function(x) x.id.Trim().Equals(c.Trim())).ToList()
and
Dim filteredlist = rawList.Where(Function(x) x.id.Trim() = (c.Trim())).ToList()
Please look into it thanks!

Answer 1

Looks like you have it backwards. Typically you have a list for looking for something first and not iterate through that list which IMHO takes longer.
Filter Linq Child Collection by another List/Array
Public Class POC
Public Property Id As Integer
Public Property Desc As String
Public Property Orders As List(Of Order)
End Class
Public Class Order
Public Property Id As Integer
Public Property Desc As String
End Class
Private Shared Function GetOrders(numberOfOrders As Integer) As List(Of Order)
Dim orders = New List(Of Order)()
For i As Integer = 1 To numberOfOrders
orders.Add(New Order() With { .Id = i, .Desc = "{i} Order" })
Next
Return orders
End Function
Private Shared Function GetPOCOsAndOrders() As List(Of POC)
Return New List(Of POC)() From { _
New POC() With { .Id = 1, .Desc = "John", .Orders = GetOrders(1) },
New POC() With { .Id = 2, .Desc = "Jane", .Orders = GetOrders(2) },
New POC() With { .Id = 3, .Desc = "Joey", .Orders = GetOrders(3) }
End Function
Private Shared Sub Main(args As String())
Dim orders = New List(Of Integer)() From { 2, 3 }
Dim items = GetPOCOsAndOrders()
Dim peopleAndOrdersWhereOrderNumberIsGreaterThanTwo = items.Where(Function(x) x.Orders.Any(Function(y) orders.Contains(y.Id)))
'I should only get the last two people out of three and their orders
peopleAndOrdersWhereOrderNumberIsGreaterThanTwo.ToList().ForEach(Function(x) Console.WriteLine("{x.Id} {x.Desc} {x.Orders.Count}"))
Console.ReadLine()
End Sub

Answer 2

There are many silght variations possible with the limited information you have given us, but a working example is:
Option Infer On
Option Strict On
Module Module1
Public Class datum
Property Id As String
Property Name As String
Public Sub New()
' empty constructor
End Sub
Public Sub New(Id As String, Name As String)
Me.Id = Id
Me.Name = Name
End Sub
End Class
Sub Main()
' sample data...
Dim rawData = New List(Of datum)
rawData.Add(New datum("cat", "Lulu"))
rawData.Add(New datum("cat", "Uschi"))
rawData.Add(New datum("snake", "Sid"))
rawData.Add(New datum("fox", "Reynard"))
rawData.Add(New datum("mouse", "Jerry"))
' what to look for:
Dim listIds As New List(Of String) From {"CAT", "mouse", "ELK"}
' somewhere to store the results:
Dim dict As New Dictionary(Of String, List(Of String))
' filter by what to look for:
For Each c In listIds
Dim foundItems = rawData.Where(Function(x) String.Compare(x.Id, c, StringComparison.OrdinalIgnoreCase) = 0)
' only add items to the dictionary if the Id was found:
If foundItems.Count() > 0 Then
' use the case of the id from the raw data:
dict.Add(foundItems(0).Id, foundItems.Select(Function(f) f.Name).ToList())
End If
' alternative which includes dictionary entries where the Id was not found:
'dict.Add(If(foundItems.Count = 0, c, foundItems(0).Id), foundItems.Select(Function(f) f.Name).ToList())
Next
' show the dictionary contents:
For Each kvp In dict
Console.WriteLine(kvp.Key & ": " & String.Join(", ", kvp.Value))
Next
Console.ReadLine()
End Sub
End Module
Output:
cat: Lulu, Uschi
mouse: Jerry
I have included commented-out code for some variations you may want.