How to Parse a Fully Qualified Path into Component Parts

MORE INFORMATION

The code in this article parses the fully qualified path into the following component parts:

• Drive
• Path
• Filename
• Extension

It parses the path from back to front (end to beginning) searching for the backslash (\) and colon (:) delimiters.

Step-by-Step Example

1. Start a new project in Visual Basic. Form1 is created by default.
2. Add a command button (Command1) and a text box (Text1) to Form1.
3. Place the following code in the Command1_Click event:

      Sub Command1_Click ()
         TempPath$ = Text1
   
         DriveLetter = ""
         DirPath = ""
         Filename = ""
         Extension = ""
   
         If Mid(TempPath$, 2, 1) = ":" Then     ' Find the drive letter.
            DriveLetter = Left(TempPath$, 2)
            TempPath$ = Mid(TempPath$, 3)
         End If
   
         PathLength% = Len(TempPath$)
         For OffSet% = PathLength% To 1 Step -1  ' Find the next delimiter.
            Select Case Mid(TempPath$, OffSet%, 1)
   
               Case ".": ' This indicates either an extension or a . or a ..
               ThisLength% = Len(TempPath$) - OffSet%
               If ThisLength% >= 1 And ThisLength% <= 3 Then ' Extension
                  Extension = Mid$(TempPath$, OffSet%, ThisLength% + 1)
               End If
               TempPath$ = Left(TempPath$, OffSet% - 1)
   
               Case "\": ' This indicates a path delimiter.
               ThisLength% = Len(TempPath$) - OffSet%
               If ThisLength% >= 1 And ThisLength% <= 8 Then ' Filename
                  Filename = Mid$(TempPath$, OffSet% + 1, ThisLength%)
                  TempPath$ = Left(TempPath$, OffSet%)
                  FileNameFound% = True
                  Exit For
               End If
   
               Case Else
            End Select
         Next OffSet%
   
         If FileNameFound% = False Then
            Filename = TempPath$
         Else
            DirPath = TempPath$
         End If
   
         ' Print to form for display.
         Form1.Cls
         Form1.Print "Drive:", DriveLetter
         Form1.Print "Path:", DirPath
         Form1.Print "Filename:", Filename
         Form1.Print "Extension:", Extension
      End Sub
   						

4. Press the F5 key to run the program.
5. Type a path into the Text1 box.
6. Click the Command1 button.

The program should break the path up into its component parts and print the result on Form1.

NOTE: This program does not attempt to validate the path structure. It assumes that the path you have typed in is a valid path.