Visual Basic Fundamentals: Development for Absolute Beginners

While Iterations and Reading Data from a Text File - 11

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Description

In this lesson we'll both learn a new type of iteration statement (While) and will learn how to utilize the StreamReader class to stream data from a file to the Console window. Additionally, we'll learn how to add new files to our project, how to set properties of our file using the Properties window, how to add a using statement as a means of resolving a class name referenced in our code to the namespace in which it is defined, and more.

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    The Discussion

    • karim

      Always great BOB
      very intuitive, nice explanation
      wishes from Morocco

    • golnazal

      open.

    • harry

      G'day Bob,
      (btw - enjoying the vid's - going to be excellent resources for my students)

      Would it have been "better" (more obvious) to use a "do until IsNothing(line) ... loop" construct rather than the "while ... end while" ? Or perhaps even the "do ... loop until IsNothing(line)" ?

      The "benefit" would be the immediate removal of the "double-negative", which, to be honest, as a vet of 4 decades of coding still trips me up occasionally ;') I know my students struggled with it just last week, hence why it is still "fresh" in my mind :)

      Kind regards,

      Harry

    • BobTabor

      @harry:  Great, great tip!  You're right, I probably could have written than using a different looping structure and made it a "positive" rather than a double-negative.  Smiley  Thank you and best wishes to your students!

    • Rick

      I have noticed that with Harry's Do until method you no longer need the If then statement also.. Thanks for the tip Harry and thanks Bob for the While method I see where they can both be very useful.

    • ZeroShek

      I was looking for an open thread to thank you on previous 10 tutorials but all threads were closed....finally got the opportunity ...Thanks for creating tutorials that are so simple yet teaches you a lot...are there videos for WinForms apps too using VB..if yes plz share the link..I'll be very grateful to you..well that is already I'm.

    • Beth

      Thank you for these great videos! Bob - your delivery is excellent. Great voice, cadence, inflection, etc. Of course it helps that the subject matter is important to me, but that's beside the point!

    • meldoc

      Thank you for this excellent series, a great resource.

    • Kent Haunschild

      Tried Harry's method the Do Until...Loop
      coded like this:
      Dim myReader As StreamReader = New StreamReader("values.txt")

      Dim line As String = ""
      Do Until IsNothing(line)
      line = myReader.ReadLine()
      Console.WriteLine(line)
      Loop

      myReader.Close()
      Console.ReadLine()
      The program ran I.E. gave the correct output to the display, but with following errors:

      A first chance exception of type 'System.IndexOutOfRangeException' occurred in UnderstandingArrays.exe
      A first chance exception of type 'System.IndexOutOfRangeException' occurred in UnderstandingArrays.exe
      A first chance exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.dll

      I realize the lesson was on using the While()...IsNothing but as wondering what else is wrong with my code.

    • BobTabor

      @Rick: Agreed.

      @ZeroShek:  Thanks!  I'm sure there are videos out there, but not by me.  Sorry!

      @Beth: Ah, thanks Beth!

      @meldoc: Thank you!

      @Kent Haunschild: Hi!  check this out ... it uses Do ... Loop Until properly:

      http://msdn.microsoft.com/en-us/library/aa720461(v=vs.71).aspx

    • jueban

      so good!

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