I could not find anything in your book about the string manipulation functions, so I went to the VB 2005 Online Help instead. According to Microsoft "Help" all these 1-based functions still exist in VB -- including Mid(), Left(), and Right(). Of course there are additional 0-based "methods" of string objects that do similar functions now.

Much of my old VB 6.0 Code is full of string manipulations, parsing the commands and responses to and from devices with serial port or ethernet interfaces. When I try to use these functions in my VB 2005 the Mid() function works, but the Left() and Right() functions do not. Intellisense finds valid Left() and Right() functions -- but these have nothing to do with strings.

Do you know why this compatibility problem exists, and can you verify that it exists or not in you own version of VB 2005?


Truman Byron Thomas

Those functions do still exist, although Microsoft doesn't really encourage their use. The "preferred" methods are the 0-based String methods such as String.Substring. (It's annoying that there are no String.Left and String.Right methods.)

But if you want the old functions, they're in Microsoft.VisualBasic.Strings. For example:

    left_text = Microsoft.VisualBasic.Strings.Left$("some text")

If you use them a lot (it sounds like you do), then you can use Imports to make it a bit easier:

    Imports Microsoft.VisualBasic.Strings
    ...
        left_text = Left$("some text")

I hope that helps.


Rod
[email protected]
Author of "Visual Basic 2005 Programmer's Reference"
http://www.vb-helper.com/vb_prog_ref.htm

Thanks for finding the Left and Right string functions for me. I have verified that the first part of your answer works on my VB 2005: That is, if you explicitly reference the function names by prefixing them with "Microsoft.VisualBasic.Strings.". However, when I added an
"Imports Microsoft.VisualBasic.Strings" statement just before the Public Class (form) statement, I could NOT remove the explicit reference. It gives a error. So in this case the Imports statement does not work.

Do you think this is a VS 2005 bug that should be reported to Microsoft?

Truman Byron Thomas

Odd. That worked for me yestderday but not today. I think it's getting confused and trying to use a different namespace's version instead, probably the form's version of Left and Right which deal with the form's position not strings. Unfortunately I can't figure out how to change the order in which it searches namespaces to tell it to search Microsoft.VisualBasic.Strings before it searches System.Windows.Forms. Of course that would probably lead to confusion when you wanted to use the Forms properties.

You could report it as a bug but I suspect Microsoft will say this is by design. Because this is a VB 6 compatability issue, I doubt it would get high priority.

You could import Microsoft.VisualBasic and then use Strings.Left. Or you could define an alias for the import like this:

    Imports Str = Microsoft.VisualBasic.Strings
    ...
        left_text = Str.Left$("some text")

I think I would take one of these two approaches. Or use the newer String methods, even if they are less convenient for this.

Rod

Rod
[email protected]
Author of "Visual Basic 2005 Programmer's Reference"
http://www.vb-helper.com/vb_prog_ref.htm

Byron, Rod,

The namespace and Imports behavior you describe here is similar to a problem I am having. The Imports statement does not seem to allow my VB.NET code to recognize that Exception is part of the System namespace. Check out my post “Compilation Error ASP.NET 2.0 & IIS 5.1” dated 4/17/2006 in the ASP and ASP.NET > ASP.NET 2.0 Beginner forum.

Did you get Compiler Error Message BC30392? Have you tried using the ASP.NET Development Server? That changes the behavior in my case and my code compiles. I also found that recoding in C# also allows the application to work!

G. Mitchell