Cancellation Coding

I need support to sort out the error as I am unable to read and write a two different text file into two text boxes, combo box for Surname and the label for price.Also looked for help in many ways and this is my code.

Dim BookedFile As System.IO.StreamReader
        BookedFile = IO.File.OpenText("G:\Starshine Amateur Dramatic Society\SADs Document\Booked_File4thOct.txt")
        Do While BookedFile.Peek <> -1
            Dim SurnameLine As String = BookedFile.ReadLine()
            cmboboxSName.Items.Add(SurnameLine)