Arraylist issue in vb.net 2008

[jake007]

I am trying to populate an array list from a fixed length file. The code processes through the file ok, but my arraylist ends up with 17 copies (the number of records in the file) of the last record? Her is the code

Public Sub LoadMachineArray()
Dim NewMachine As New Machine
Dim sr As StreamReader
Dim LineData As String

MachineList.Clear()

sr = New StreamReader("c:\SupplyData\Machines.txt")

LineData = sr.ReadLine
Do While (Not LineData Is Nothing)

NewMachine.MachineId = Mid(LineData, 1, 19).Trim
NewMachine.Type = Mid(LineData, 20, 19).Trim
NewMachine.Supply(0) = Mid(LineData, 40, 19).Trim
NewMachine.Supply(1) = Mid(LineData, 60, 19).Trim
NewMachine.Supply(2) = Mid(LineData, 80, 19).Trim
NewMachine.Supply(3) = Mid(LineData, 100, 19).Trim
NewMachine.Supply(4) = Mid(LineData, 120, 19).Trim
NewMachine.Supply(5) = Mid(LineData, 140, 19).Trim
NewMachine.Supply(6) = Mid(LineData, 160, 19).Trim
NewMachine.Supply(7) = Mid(LineData, 180, 19).Trim
NewMachine.Supply(8) = Mid(LineData, 200, 19).Trim
NewMachine.Supply(9) = Mid(LineData, 220, 19).Trim
NewMachine.Supply(10) = Mid(LineData, 240, 29).Trim

MachineList.Add(NewMachine)
LineData = sr.ReadLine
Loop
'NewMachine = Nothing

For Each mach As Machine In MachineList
ListBox1.Items.Add(mach.MachineId & "-" & mach.Type & "-" & mach.Supply(0))
Next
End Sub


The list box (listbox1) ends up with 17 copies of the last record?

 

[jebenson]

This is happening because you are using the same Machine object (NewMachine) for each line. So you store the first Machine with its data, then change all of the values in the Machine object when you read the second line, and so forth. The fix is easy, just create a new Machine object for each iteration of the loop:

Do While (Not LineData Is Nothing)

[red]NewMachine = New Machine[/red]

'other code

Loop


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Arrrr, mateys! Ye needs ta be preparin' yerselves fer Talk Like a Pirate Day!

 

[jake007]

Thanks jebenson. Can't believe i missed that. Looked at the code for too long I guess.