bugs, How to detect that NO CD exists in the CHOSEN DRIVE

Hi,

I have a DriveList Box ( drvChoose) and a Directory ListBox ( dirDirect)
in my ActiveX control. When the users choose a drive, then the directoryList
box changes to display the directories of that drive. This works fine. BUt
the problem is that when no CD exists in the CD ROM drive and users choose
that drive, then my program fails. It shows diagnoal black lines across my
activeX control.

What code do I need to add so that when no CD/ DVD exists in the CD drive
and if user selects that drive, then an error message is displayed which says
there is no CD/ DVD in this drive. Please insert it to continue.

Below is the code I am using.

Private Sub drvChoose_Change()

dirDirect.Path = drvChoose.Drive '--WHEN NO CD in the CHOSEN DRIVE, It
FAILS

End Sub

Any help will be appreciated.

Thanks
--
pmud

You need to use error-trapping! Here's an example from a little UserControl
I put together that ties all three native file controls together:

Private Sub Drive1_Change()
Static Busy As Boolean

' Avoid recursion.
If Not Busy Then
' Watch out for invalid/unavailable drives!
On Error Resume Next
Dir1.Path = Drive1.Drive
Select Case Err.Number
Case 0
' Let user know drive was changed.
RaiseEvent DriveChanged(Drive1.Drive)
' Remember this as a "good" drive.
m_LastGoodDrive = Drive1.Drive
Case 68
' Bad choice, stick with what was.
Err.Clear
RaiseEvent DeviceUnavailable(Drive1.Drive)
Busy = True
Drive1.Drive = m_LastGoodDrive
Busy = False
Case Else
' Huh?
Debug.Print Err.Number, Err.Description
End Select
End If
End Sub

Later... Karl
--
Working without a .NET?
http://classicvb.org/

Hi Karl,

My question might seem silly but when I use your code, I get the error
message, "Event not found" and it highlights " RaiseEvent DriveChanged" event
in the code . I know its coming because I have not specified thsi event in my
code. But how to specify events in my code?

Thanks
--
pmud

Well, you use the Event declaration, actually. <G> Remember, I said that
was taken from a UserControl I'd written? Up top, in that, I have this:

' Raised events.
Public Event DriveChanged(ByVal NewDrive As String)
Public Event PathChanged(ByVal NewPath As String)
Public Event FileSelected(ByVal NewFile As String)
Public Event DeviceUnavailable(ByVal InvalidDrive As String)

You're free to take that (RaiseEvent call) out, of course, if you're not
needing it.

Later... Karl
--
Working without a .NET?
http://classicvb.org/

i Karl,

I have never used error handling before. Could you suggest some quick lins
which I can read to get how to write error handling code.

Thanks

--
pmud


"Karl E. Peterson" wrote:

Hey Carl,

How do you come to know about error numbers?

Thanks
--
pmud

http://www.google.com/search?q=error +handling+vb
--
Working without a .NET?
http://classicvb.org/

Right-click in any code window, select Toggle, then "Break on Unhandled
Errors".

When your program throws an error, pop into the Immediate window, and type:

?err.number, err.description

Later... Karl
--
Working without a .NET?
http://classicvb.org/

Your post encouraged me to add something I wrote a long time ago to my
website. If you'd like to see how I put these three together into a single
usercontrol, please visit:

http://vb.mvps.org/samples/FileControls

Thanks... Karl
--
Working without a .NET?
http://classicvb.org/