DOCUMENT:Q192689  17-SEP-1998  [vbwin]
TITLE   :HOWTO: Get UNC Path From a Mapped Network Share's Drive Letter
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:WINDOWS:4.0,5.0,6.0
OPER/SYS:WINDOWS
KEYWORDS:

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The information in this article applies to:

 - Microsoft Visual Basic Learning, Professional, and Enterprise Editions
   for Windows, version 6.0
 - Microsoft Visual Basic Control Creation, Learning, Professional, and
   Enterprise Editions for Windows, version 5.0
 - Microsoft Visual Basic Standard, Professional, and Enterprise Editions,
   32-bit only, for Windows, version 4.0
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SUMMARY
=======

Most network client software allows you to refer to network drives through
the use of mapped drive letters or the use of syntax known as UNC notation
(Universal Naming Convention). Use of UNC notation requires that you know
the name of the server and share, while a mapped drive letter only requires
the drive letter once the connection has been established. At times, it may
be necessary to determine the UNC path to a server given only it's mapped
drive letter. This article demonstrates a method for obtaining this
information.

MORE INFORMATION
================

Step-by-Step Example
--------------------

1. Map a drive letter to any available network share and make note of
   the letter assigned.

2. Create a new Visual Basic project. Form1 is created by default.

3. Add a CommandButton to Form1.

4. Paste the following code into Form1's code window:

      Option Explicit

      Private Const RESOURCETYPE_ANY = &H0
      Private Const RESOURCE_CONNECTED = &H1

      Private Type NETRESOURCE
         dwScope As Long
         dwType As Long
         dwDisplayType As Long
         dwUsage As Long
         lpLocalName As Long
         lpRemoteName As Long
         lpComment As Long
         lpProvider As Long
      End Type

      Private Declare Function WNetOpenEnum Lib "mpr.dll" Alias _
         "WNetOpenEnumA" (ByVal dwScope As Long, ByVal dwType As Long, _
         ByVal dwUsage As Long, lpNetResource As Any, lphEnum As Long) _
         As Long

      Private Declare Function WNetEnumResource Lib "mpr.dll" Alias _
         "WNetEnumResourceA" (ByVal hEnum As Long, lpcCount As Long, _
         lpBuffer As Any, lpBufferSize As Long) As Long

      Private Declare Function WNetCloseEnum Lib "mpr.dll" ( _
         ByVal hEnum As Long) As Long

      Private Declare Function lstrlen Lib "kernel32" Alias "lstrlenA" _
         (ByVal lpString As Any) As Long

      Private Declare Function lstrcpy Lib "kernel32" Alias "lstrcpyA" _
         (ByVal lpString1 As Any, ByVal lpString2 As Any) As Long

      Private Sub Command1_Click()
         MsgBox LetterToUNC("F:") ' <<<<<<<<<<<<<<<<<<<<<<<<<<<<<
      End Sub

      Function LetterToUNC(DriveLetter As String) As String
         Dim hEnum As Long
         Dim NetInfo(1023) As NETRESOURCE
         Dim entries As Long
         Dim nStatus As Long
         Dim LocalName As String
         Dim UNCName As String
         Dim i As Long
         Dim r As Long

         ' Begin the enumeration
         nStatus = WNetOpenEnum(RESOURCE_CONNECTED, RESOURCETYPE_ANY, _
            0&, ByVal 0&, hEnum)

         LetterToUNC = "Drive Letter Not Found"

         'Check for success from open enum
         If ((nStatus = 0) And (hEnum <> 0)) Then
            ' Set number of entries
            entries = 1024

            ' Enumerate the resource
            nStatus = WNetEnumResource(hEnum, entries, NetInfo(0), _
               CLng(Len(NetInfo(0))) * 1024)

            ' Check for success
            If nStatus = 0 Then
               For i = 0 To entries - 1
                  ' Get the local name
                  LocalName = ""
                  If NetInfo(i).lpLocalName <> 0 Then
                     LocalName = Space(lstrlen(NetInfo(i).lpLocalName) + 1)
                     r = lstrcpy(LocalName, NetInfo(i).lpLocalName)
                  End If

                  ' Strip null character from end
                  If Len(LocalName) <> 0 Then
                     LocalName = Left(LocalName, (Len(LocalName) - 1))
                  End If

                  If UCase$(LocalName) = UCase$(DriveLetter) Then
                     ' Get the remote name
                     UNCName = ""
                     If NetInfo(i).lpRemoteName <> 0 Then
                        UNCName = Space(lstrlen(NetInfo(i).lpRemoteName) _
                           + 1)
                        r = lstrcpy(UNCName, NetInfo(i).lpRemoteName)
                     End If

                     ' Strip null character from end
                     If Len(UNCName) <> 0 Then
                        UNCName = Left(UNCName, (Len(UNCName) _
                           - 1))
                     End If

                     ' Return the UNC path to drive
                     LetterToUNC = UNCName

                     ' Exit the loop
                     Exit For
                  End If
               Next i
            End If
         End If

         ' End enumeration
         nStatus = WNetCloseEnum(hEnum)
      End Function

5. Change the code in Command1's Click event to refer to the drive letter
   created by step 1.

6. Run the sample.

7. Click the CommandButton. The UNC path to the mapped drive is shown in a
   message box.

Additional query words: kbDSupport kbDSD kbVBp kbVBp400 kbVBp500 kbVBp600
KbVBA kbAPI kbSDKWin32 kbWNet
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Version           : WINDOWS:4.0,5.0,6.0
Platform          : WINDOWS
Issue type        : kbhowto

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