How To Get a Long Filename from a Short Filename

The Dir() function can be used to return a long filename but it does not include path information. By parsing a given short path/filename into its constituent directories, you can use the Dir() function to build a long path/filename. This article demonstrates how to accomplish this behavior.

The following code example includes a function that converts short filenames into their long filename equivalents and also includes a simple demonstration of the function's use.

Step-by-Step Example

1. Start Visual Basic. Form1 is created by default.
2. Place a CommandButton on Form1.
3. From the Insert menu, select Module to add a single code module to the project.
4. Add the following code to Module1:

         Public Function GetLongFilename _
           (ByVal sShortName As String) _
           As String
   
           Dim sLongName As String
           Dim sTemp As String
           Dim iSlashPos As Integer
   
           'Add \ to short name to prevent Instr from failing
           sShortName = sShortName & "\"
   
           'Start from 4 to ignore the "[Drive Letter]:\" characters
           iSlashPos = InStr(4, sShortName, "\")
   
           'Pull out each string between \ character for conversion
           While iSlashPos
             sTemp = Dir(Left$(sShortName, iSlashPos - 1), _
               vbNormal + vbHidden +    vbSystem + vbDirectory)
             If sTemp = "" Then
               'Error 52 - Bad File Name or Number
               GetLongFilename = ""
               Exit Function
             End If
             sLongName = sLongName & "\" & sTemp
             iSlashPos = InStr(iSlashPos + 1, sShortName, "\")
           Wend
   
           'Prefix with the drive letter
           GetLongFilename = Left$(sShortName, 2) & sLongName
   
         End Function
   
   					

5. Add the following to the Command1_Click event:

         Private Sub Command1_Click()
   
           'Assumes C:\Program Files\Common Files is a valid path
           Print GetLongFilename("C:\PROGRA~1\COMMON~1")
   
         End Sub
   
   					

6. Choose Start from the Run menu, or press the F5 key to start.
7. Click the CommandButton. If the path you have supplied is valid, the long equivalent will be printed on the form. If it is not valid, nothing will print, in which case you will need to supply a valid short filename in the Command1_Click event code.

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