Microsoft KB Archive/100834

Knowledge Base

VB3 Find Next Available Drive Letter (for Network Connect)

Article ID: 100834

Article Last Modified on 12/9/2003

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APPLIES TO

• Microsoft Visual Basic 2.0 Standard Edition
• Microsoft Visual Basic 3.0 Professional Edition
• Microsoft Visual Basic 2.0 Professional Edition
• Microsoft Visual Basic 3.0 Professional Edition

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This article was previously published under Q100834

SUMMARY

The Visual Basic program in this article shows by example how to find the next available (unused) drive letter in Windows. This could be useful when making network connections to a new drive letter.

MORE INFORMATION

Step-by-Step Example

The Freedrive function defined below returns the next drive letter available in Windows, followed by a colon (:).

1. Start Visual Basic. Form1 is created by default.

2. Add the following code to the General Declarations section of Form1:

      ' Enter the following Declare statement as one, single line:
      Declare Function GetDriveType Lib "kernel"
         (ByVal nDrive As Integer) As Integer
   
      Function Freedrive ()
         Dim DriveNum As Integer, FirstFreeDrive As String
         Dim FirstDrive As Integer
         DriveNum = -1
         Do
            DriveNum = DriveNum + 1   ' start at drive zero.
            FirstDrive% = GetDriveType(DriveNum)
            ' GetDriveType returns zero if it cannot determine drive
            ' type or returns 1 if the specified drive does not exist.
         Loop Until FirstDrive% = 0
         ' DriveNum of 0 means Drive A, 1=B, 2=C, 3=D, 4=E, 5=F, and so on:
         FirstFreeDrive = Chr$(DriveNum + 65) + ":"
         Freedrive = FirstFreeDrive
      End Function
                           

3. In the Form_click event, add the following statements:

      Sub Form_Click ()
   
         Cls
         Print "The next available (unused) drive letter is: "; Freedrive()
   
         ' More handy tips: The "App" object below is found in VB 2.0
         ' and 3.0 (but not 1.0).
         Print "The title for the EXE in Windows Task Manager: "; app.Title
         Print "The name of this EXE, or project in VB, is: "; app.EXEName
         Print "The path to this application is: "; app.Path
   
      End Sub
                           

4. Run the program, and click the form.

Additional query words: 2.00 3.00

Keywords: kbnetwork kbcode KB100834

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