Sort List(of Object) by object properties - vb.net

Question

I'm trying to achieve something where the answer is already given for. But it's in c# and I don't have any knowledge what-so-ever over c# so I'm looking for a vb.net alternative.
I made a class called BomItem which has several properties like quantity, description etc.
I add these BomItems into a List(of BomItem) but now I would like to sort them according to a property. How can you sort the items based on the ItemNumber property?
Here is the link to the c# solution I found.
My class code
Public Class BomItem
Public Property ItemNumber As String
Public Property Description As String
Public Property Quantity As Double
Public Property Material As String
Public Property Certificate As String
End Class
How I add the BomRow objects
_NewBomList.Add(New BomItem() With {
.ItemNumber = oRow.ItemNumber,
.Description = oPropSet.Item("Description").Value,
.Quantity = oRow.TotalQuantity,
.Material = oPropSet.Item("Material").Value,
.Certificate = CustomPropertySet.Item("Cert.").Value})
Comparer
Public Class NaturalSort
Implements IComparer
Public Function Compare(ByVal x As Object,
ByVal y As Object) As Integer Implements IComparer.Compare
' [1] Validate the arguments.
Dim s1 As String = x
If s1 = Nothing Then
Return 0
End If
Dim s2 As String = y
If s2 = Nothing Then
Return 0
End If
Dim len1 As Integer = s1.Length
Dim len2 As Integer = s2.Length
Dim marker1 As Integer = 0
Dim marker2 As Integer = 0
' [2] Loop over both Strings.
While marker1 < len1 And marker2 < len2
' [3] Get Chars.
Dim ch1 As Char = s1(marker1)
Dim ch2 As Char = s2(marker2)
Dim space1(len1) As Char
Dim loc1 As Integer = 0
Dim space2(len2) As Char
Dim loc2 As Integer = 0
' [4] Collect digits for String one.
Do
space1(loc1) = ch1
loc1 += 1
marker1 += 1
If marker1 < len1 Then
ch1 = s1(marker1)
Else
Exit Do
End If
Loop While Char.IsDigit(ch1) = Char.IsDigit(space1(0))
' [5] Collect digits for String two.
Do
space2(loc2) = ch2
loc2 += 1
marker2 += 1
If marker2 < len2 Then
ch2 = s2(marker2)
Else
Exit Do
End If
Loop While Char.IsDigit(ch2) = Char.IsDigit(space2(0))
' [6] Convert to Strings.
Dim str1 = New String(space1)
Dim str2 = New String(space2)
' [7] Parse Strings into Integers.
Dim result As Integer
If Char.IsDigit(space1(0)) And Char.IsDigit(space2(0)) Then
Dim thisNumericChunk = Integer.Parse(str1)
Dim thatNumericChunk = Integer.Parse(str2)
result = thisNumericChunk.CompareTo(thatNumericChunk)
Else
result = str1.CompareTo(str2)
End If
' [8] Return result if not equal.
If Not result = 0 Then
Return result
End If
End While
' [9] Compare lengths.
Return len1 - len2
End Function
End Class

Answer 1

Use LINQ OrderBy:
_NewBomList.OrderBy(Function(bi) bi.ItemNumber)
and for descending:
_NewBomList.OrderByDescending(Function(bi) bi.ItemNumber)
If you want a numeric order in your string you have to convert it to an integer first:
_NewBomList.OrderBy(Function(bi) Integer.Parse(bi.ItemNumber))
Edit:
To provide a custom IComparer for the OrderBy extension you have to create a class which implements IComparer(Of String) where String are your ItemNumbers to compare:
Class ItemNumberComparer
Implements IComparer(Of String)
Public Function Compare(String x, String y)
Dim ix As String() = x.Split("."C)
Dim iy As String() = y.Split("."C)
Dim maxLen As Integer = Math.Max(ix.Length, iy.Length)
For i As Integer = 0 To maxLen - 2
If ix.Length >= i AndAlso iy.Length >= i Then
If Integer.Parse(ix(i)) < Integer.Parse(iy(i)) Then
Return -1 'If x.i is LT y.i it must be smaller at all
ElseIf Integer.Parse(ix(i)) > Integer.Parse(iy(i)) Then
Return 1 'If x.i is GT y.i it must be bigger all
End If
End If
Next
'This code is only executed if x and y differ at last number or have different ´number of dots
If ix.Length = iy.Length Then
Return Integer.Parse(ix(ix.Length - 1)).CompareTo(Integer.Parse(iy(iy.Length - 1))) 'Only last number differs
Else
Return ix.Length.CompareTo(iy.Length) 'The number with more dots is smaller
End If
End Function
End Class
Call syntax:
Dim comparer = new ItemNumberComparer()
_NewBomList.OrderByDescending(Function(bi) bi.ItemNumber, comparer)

Answer 2

This C# code from that other thread:
List<Order> SortedList = objListOrder.OrderBy(o=>o.OrderDate).ToList();
equates to this VB code:
List(Of Order) SortedList = objListOrder.OrderBy(Function(o) o.OrderDate).ToList()
As you can see, very little changes. You just have to know the syntax for generics and lambda expressions.
You should be aware, though, that this code does NOT sort your list. It sorts the items in the list and then adds them to a new list in that order. This is perfectly fine for many applications but if you're using that same list elsewhere then you won't see the new order there. While there are a few variations, one way to actually sort the list in place is like this:
objListOrder.Sort(Function(o1, o2) o1.OrderDate.CompareTo(o2.OrderDate))

Answer 3

Another solution would be to implement the IComparable (see MSDN ref) interface. This interface is designed to sort your objects on a custom way :
Public Class BomItem
Implements IComparable
Public Property ItemNumber As String
Public Property Description As String
Public Property Quantity As Double
Public Property Material As String
Public Property Certificate As String
Public Function CompareTo(obj As Object) As Integer
Dim bom = CType(obj, BomItem)
If Not bom Is Nothing then
Return Me.ItemNumber.CompareTo(bom.ItemNumber)
Else
Throw New ArgumentException("Object is not a BomItem")
End If
End Class
and you can sort the list this way :
Dim myList As New List(Of BomItem)
'Code to add your BomItems
myList.Sort()
This will actually sort your list, it does not create a new list.