(VB.NET) Find all duplicates in a list of objects based on multiple properties - vb.net

Question

I have a list of CommissionStatement objects which i created. I need to create a new list which only holds the duplicates found in this list based on 3 properties: Firm; Provider; and Total (ie each of these 3 have to be the same in 2 or more objects for it to be recognized as a duplicate)
Object is a simple object of strings at the moment.
Private Class CommissionStatement
Property Provider As String
Property Firm As String
Property Source As String
Property Media As String
Property Total As String
Property Received As String
End Class
I have a list of all CommissionStatments as follows:
Dim fileLocation As String = importText.Text
Dim csvText As String = My.Computer.FileSystem.ReadAllText(fileLocation).Replace(", ", " ")
Dim providerString As String = ""
Dim allStatements = New List(Of CommissionStatement)
Dim countIndex As Integer = 0, maxIndex As Integer = csvText.Split(vbLf).Length
For Each line As String In csvText.Split(vbLf)
'' Remove the top row
countIndex += 1
If countIndex = 1 Then
Continue For
End If
statementProgress.Value = ((countIndex / maxIndex) * 100)
'' Build the New commissionStatement object and add it to the allStatements list
If Not line = "" Then
Dim commissionStatement = New CommissionStatement
With commissionStatement
.Provider = line.Split(",")(0)
.Firm = line.Split(",")(1)
.Source = line.Split(",")(2)
.Media = line.Split(",")(3)
.Total = line.Split(",")(4)
End With
providerString &= commissionStatement.Provider & ","
allStatements.Add(commissionStatement)
End If
Next
First post on StackOverflow so sorry if its not very clear! The duplicate list needs to also be a list of CommissionStatements which contain the duplicates from the allStatements list based on Firm Provider and Total

Answer 1

Your best bet is to use a lambda expression. The function below should do what you ask.
Private Function GetDuplicateCommisionStatements(tempStatement As CommissionStatement) As List(Of CommissionStatement)
Return allStatements.FindAll(Function(x) x.Firm = tempStatement.Firm And x.Provider = tempStatement.Provider And x.Total = tempStatement.Total)
End Function
And use it like this..
duplicatelist = GetDuplicateCommisionStatements(testCommisionStatement)
using your own object names of course.
Incidentally, you could shorten the sub using the With statement like below
Private Function GetDuplicateCommisionStatements(tempStatement As CommissionStatement) As List(Of CommissionStatement)
With tempStatement
Return allStatements.FindAll(Function(x) x.Firm = .Firm And x.Provider = .Provider And x.Total = .Total)
End With
End Function