Last line of sequential access file

[chixor1]

I am writing an order number to a txt file.
Each new order takes the order number form the txt file, and apprends by 1 to create the new order number.
However I cant seem to find how to read the last line of the txt file, so I do not get duplicate order numbers?

for example
My text file has the following order numbers:

3403
3404


My code for the text file is as follows

 
        Dim orderNumStreamReader As IO.StreamReader
        Dim orderNumStreamWriter As IO.StreamWriter
        Dim orderNum As Integer
        Dim newOrderNum As Integer
 
 
 
 
        If IO.File.Exists("OrderNum.txt") Then
 
            orderNumStreamReader = IO.File.OpenText("OrderNum.txt")
        Else
            MessageBox.Show("File Does not Exist", "OrderNumber", MessageBoxButtons.OK, _
                MessageBoxIcon.Information)
 
        End If
 
 
        orderNum = orderNumStreamReader.ReadLine()
        orderNumStreamReader.Close()
 
 
 
 
 
        newOrderNum = orderNum + 1
 
        If IO.File.Exists("OrderNum.txt") Then
 
            orderNumStreamWriter = IO.File.AppendText("OrderNum.txt")
        Else
            MessageBox.Show("File Does not Exist", "OrderNumber", MessageBoxButtons.OK, _
                MessageBoxIcon.Information)
 
        End If
 
 
        orderNumStreamWriter.WriteLine(newOrderNum)
 
 
        orderNumStreamWriter.Close()
 
 

Now when I run my app, it reads the first line of the order number and appends that, giving me duplicate order numbers.

[kenobewan]

I wonder if this would be better done using xml. If you have a database, you could also update the xml to the database.