ACC: How to Return an UNC Path from an Existing Drive Letter (151027)

MORE INFORMATION

1. Create a module and type the following lines in the Declarations section:

    Option Explicit
   
         ' These represent the possible returns errors from API.
         Public Const ERROR_BAD_DEVICE = 1200&
         Public Const ERROR_CONNECTION_UNAVAIL = 1201&
         Public Const ERROR_EXTENDED_ERROR = 1208&
         Public Const ERROR_MORE_DATA = 234
         Public Const ERROR_NOT_SUPPORTED = 50&
         Public Const ERROR_NO_NET_OR_BAD_PATH = 1203&
         Public Const ERROR_NO_NETWORK = 1222&
         Public Const ERROR_NOT_CONNECTED = 2250&
         Public Const NO_ERROR = 0
   
         ' This API declaration is used to return the
         ' UNC path from a drive letter.
         Declare Function WNetGetConnection Lib "mpr.dll" Alias _
                          "WNetGetConnectionA" _
                          (ByVal lpszLocalName As String, _
                          ByVal lpszRemoteName As String, _
                          cbRemoteName As Long) As Long
   						

2. Type the following procedure:

          Function GetUNCPath(strDriveLetter As String) As String
            On Local Error GoTo GetUNCPath_Err
            Dim Msg As String, lngReturn As Long
            Dim lpszLocalName As String
            Dim lpszRemoteName As String
            Dim cbRemoteName As Long
            lpszLocalName = strDriveLetter
            lpszRemoteName = String$(255, Chr$(32))
            cbRemoteName = Len(lpszRemoteName)
            lngReturn = WNetGetConnection(lpszLocalName, _
                                          lpszRemoteName, _
                                          cbRemoteName)
            Select Case lngReturn
               Case ERROR_BAD_DEVICE
                  Msg = "Error: Bad Device"
               Case ERROR_CONNECTION_UNAVAIL
                  Msg = "Error: Connection Un-Available"
               Case ERROR_EXTENDED_ERROR
                  Msg = "Error: Extended Error"
               Case ERROR_MORE_DATA
                  Msg = "Error: More Data"
               Case ERROR_NOT_SUPPORTED
                  Msg = "Error: Feature not Supported"
               Case ERROR_NO_NET_OR_BAD_PATH
                  Msg = "Error: No Network Available or Bad Path"
               Case ERROR_NO_NETWORK
                  Msg = "Error: No Network Available"
               Case ERROR_NOT_CONNECTED
                  Msg = "Error: Not Connected"
               Case NO_ERROR
                  ' all is successful...
            End Select
            If Len(Msg) Then
               MsgBox Msg, vbInformation
            Else
               ' Display the path in a Message box or return
               ' the UNC through the function.
               MsgBox Left$(lpszRemoteName, cbRemoteName)
               GetUNCPath = Left$(lpszRemoteName, cbRemoteName)
            End If
         GetUNCPath_End:
            Exit Function
         GetUNCPath_Err:
            MsgBox Err.Description, vbInformation
            Resume GetUNCPath_End
         End Function
   						

3. To test this function, type the following line in the Debug window, and then press ENTER. A simple message box appears containing the UNC path of the specified network drive letter.

         ?GetUNCPath("h:")
   						

   NOTE: This example assumes that you have a mapped network drive assigned to driver letter H.
   
   Some of the possible return values for the GetUNCPath function include ERROR_BAD_DEVICE, ERROR_CONNECTION_UNAVAIL, and ERROR_NOT_CONNECTED.
   
   Other run-time errors could be returned from the function and error trapping should be implemented.