ChDir May Fail When Changing to a Root Directory

SUMMARY

In Microsoft Excel, the Visual Basic ChDir statement will fail if the path argument does not contain a backslash character (\). This requirement may cause problems if you use ChDir to change to a root directory, because the path of a root directory does not necessarily contain a backslash.

NOTE: When you use Microsoft Excel version 7.0 or later, you won't get an error message, but the directory won't change.

For example, the following Visual Basic code will fail

   ChDir "C:"
				

and you will receive the following error message: The following lines of code will succeed, because they each contain a backslash:

   ChDir "C:\"
				

   ChDir "C:\EXCEL\LIBRARY"
				

It is possible to incorporate error-handling into a ChDir function to prevent an error from occurring. The Visual Basic code example below demonstrates one way to do this.

Visual Basic Code Example

Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements. This Visual Basic code example displays an input box which asks you which drive or directory you would like to switch to. When you enter a drive or directory, the example checks whether the path you enter contains a backslash and adds one, if needed, before switching to that drive or directory.

To run the example, position the insertion point in the line that reads "Sub MainMacro()" and press F5.

'----------------------------------------------------------------------
Option Explicit

Sub MainMacro()
   'Dimension some variables.
   Dim NewDir As Variant
   'Prompts you to enter a drive/directory. For example, D: or C:\EXCEL.
   'If you type in an invalid directory, the subroutine will fail. For
   'example, typing just "C" (without the quotes) is not going to work.
   NewDir = InputBox("Switch to which drive/directory?")
   'If the NewDir ends in a colon, indicating it is a root directory,
   'concatenate a backslash onto the end of it. For example, C: would
   'become C:\. If you actually enter "C:\", the subroutine doesn't add
   'another backslash.
   If Right(NewDir, 1) = ":" Then
      NewDir = NewDir & "\"
   End If
   'Switches to the proper drive (the first letter in NewDir: 'Left'
   'gives us this) and directory.
   ChDrive Left(NewDir, 1)             'change to the drive (C:, etc.)
   ChDir NewDir                        'change to the directory
   'Display the name of the current directory so you know it worked.
   MsgBox "Current directory is " & CurDir()
End Sub
'----------------------------------------------------------------------
				

The If-End If routine is the error-checking procedure. Whenever you use a ChDir statement, preceding it with the If-End If routine (or some variation of it) can help prevent the "no backslash" error.