Sort an arraylist of objects by one of the properties? - vb.net

Question

Hi I have an object called item here is the code for it:
Public Class item
Private itemValue As String
Private urlfoundValue As String
Private typeValue As String
Private scorevalue As String
Public Sub New()
' Leave fields empty.
End Sub
Public Sub New(ByVal item As String, ByVal urlfound As String, ByVal type As String, ByVal score As String)
itemValue = item
urlfoundValue = urlfound
typeValue = type
scorevalue = score
End Sub
Public Property item() As String
Get
Return itemValue
End Get
Set(ByVal value As String)
itemValue = value
End Set
End Property
Public Property urlfound() As String
Get
Return urlfoundValue
End Get
Set(ByVal value As String)
urlfoundValue = value
End Set
End Property
Public Property type() As String
Get
Return typeValue
End Get
Set(ByVal value As String)
typeValue = value
End Set
End Property
Public Property score() As String
Get
Return scorevalue
End Get
Set(ByVal value As String)
scorevalue = value
End Set
End Property
I have an ArrayList of these items that I would like to sort in highest to lowest order by the Score property (is string but can be converted to int32).
The items are all store in this arraylist:
Public fullitem As New System.Collections.ArrayList()
Any suggestions on how to get the items in order by the score? Can be done in c# too.

Answer 1

A direct answer to your question is to use LINQ like this:
Dim orderdList = fullitem.Cast(Of item)() _
.OrderBy(Function(i As item) Convert.ToInt32(i.score))
fullitem = New System.Collections.ArrayList()
For Each item In orderdList
fullitem.Add(item)
Next
This uses Cast to obtain a generic IEnumerable<item> from the ArrayList which then enables you to use LINQ functions like OrderBy.
However, please note that ArrayList is now obsolete, and you should consider using List<Item> instead. If you do that then you can do something as simple as this:
Assuming you have the list defined like this:
Dim list = new List(Of item)()
You can sort it like this:
list = list.Cast(Of item)() _
.OrderBy(Function(i As item) Convert.ToInt32(i.score)) _
.ToList()