ACC: How to Retrieve Windows for Workgroups User Information

• Microsoft Access versions 1.0, 1.1, 2.0

SUMMARY

Advanced: Requires expert coding, interoperability, and multiuser skills.

Using the Microsoft Windows for Workgroups application programming interface (API), you can retrieve user information, such as user name, workgroup, domain, and computer name, about the currently running computer.

MORE INFORMATION

Windows for Workgroups includes a function called NetWkstaGetInfo() that returns information about a computer. This function is especially useful for multiuser applications.

The following procedure explains how to use Access Basic and several Windows API calls to gain access to the NetWkstaGetInfo() function:

1. Create a new module containing the following declarations and functions:

   NOTE: In the following sample code, an underscore (_) is used as a line- continuation character. Remove the underscore from the end of the line when re-creating this code in Access Basic.

   NOTE: You may have some Microsoft Windows API functions defined in an existing Microsoft Access library; therefore, your declarations may be duplicates. If you receive a duplicate procedure name error message, remove or comment out the declarations statement in your code.

   NOTE: Make sure to choose the Compile All command from the Run menu to verify that you do not receive any compilation errors.

         Option Explicit
         Declare Function NetWkstaGetInfo% Lib "NetAPI.DLL" (ByVal lServer&, _
            ByVal sLevel%, ByVal pbBuffer&, ByVal cbBuffer%, pcbTotalAvail%)
         Declare Function GlobalAlloc% Lib "Kernel" (ByVal fFlags%, _
            ByVal nSize&)
         Declare Function GlobalLock& Lib "Kernel" (ByVal hMem%)
         Declare Function GlobalUnlock% Lib "Kernel" (ByVal hMem%)
         Declare Function GlobalFree% Lib "Kernel" (ByVal hMem%)
         Declare Sub lstrcpy Lib "Kernel" (ByVal dest As Any, _
            ByVal src As Any)
         Declare Sub hmemcpy Lib "Kernel" (ByVal dest As Any, _
            ByVal src As Any, ByVal size As Long)
   
         Function GetBinInt (sobj As String, off As Integer)
            If (Asc(Mid$(sobj, off + 1, 1)) < 128) Then
               GetBinInt = Asc(Mid$(sobj, off, 1)) +_
                               Asc(Mid$(sobj, off + 1, 1)) * 256
            Else
               GetBinInt = ((&HFF - Asc(Mid$(sobj, off + 1, 1))) * 256) - _
                             Asc(Mid$(sobj, off, 1))
            End If
         End Function
   
         Function GetWorkstationInfo (sComputer As String, _
            sUserName As String, sWorkgroup As String, sLogonDomain As String)
            Dim nRetSize As Integer, nStruct, ret As Integer, dummy As Integer
            Dim hMem As Integer, lpMem As Long, sTemp As String
   
            ' Get the size of the return structure.
            ret = NetWkstaGetInfo(0&, 10, 0&, 0, nRetSize)
            If (ret <> 0) And (ret <> 2123) Then
               GetWorkstationInfo = False
               Exit Function
            End If
   
            ' Allocate memory for the structure.
            hMem = GlobalAlloc(0, CLng(nRetSize))
            nStruct = nRetSize
            If (hMem <> 0) Then
               lpMem = GlobalLock(hMem)
   
               ' Read workstation information into structure.
               ret = NetWkstaGetInfo(0&, 10, lpMem, nRetSize, nRetSize)
               If (ret = 0) Then
                  sTemp = Space(100)
                  hmemcpy sTemp, lpMem, nStruct
   
                  ' Retrieve the computer name.
                  sComputer = Space(100)
                  lpMem = CLng(GetBinInt(sTemp, 1)) +_
                              (CLng(GetBinInt(sTemp, 3)) * CLng(&H10000))
                  lstrcpy sComputer, lpMem
                  sComputer = Mid(sComputer, 1, InStr(sComputer, Chr(0)) - 1)
   
                  ' Retrieve the user name.
                  sUserName = Space(100)
                  lpMem = CLng(GetBinInt(sTemp, 5)) +_
                              (CLng(GetBinInt(sTemp, 7)) * &H10000)
                  lstrcpy sUserName, lpMem
                  sUserName = Mid(sUserName, 1, InStr(sUserName, Chr(0)) - 1)
   
                  ' Retrieve the workgroup name.
                  sWorkgroup = Space(100)
                  lpMem = CLng(GetBinInt(sTemp, 9)) +_
                              (CLng(GetBinInt(sTemp, 11)) * &H10000)
                  lstrcpy sWorkgroup, lpMem
                  sWorkgroup = Mid(sWorkgroup, 1, InStr(sWorkgroup, _
                                                        Chr(0)) - 1)
   
                  ' Retrieve the logon domain name.
                  sLogonDomain = Space(100)
                  lpMem = CLng(GetBinInt(sTemp, 15)) +_
                              (CLng(GetBinInt(sTemp, 17)) * &H10000)
                  lstrcpy sLogonDomain, lpMem
                  sLogonDomain = Mid(sLogonDomain, 1, InStr(sLogonDomain, _
                                     Chr(0)) - 1)
               End If
               ' Free the memory allocated.
               dummy = GlobalUnlock(hMem)
               dummy = GlobalFree(hMem)
            Else
               ret = -1
            End If
            GetWorkstationInfo = IIf(ret = 0, True, False)
         End Function
   
   

2. Test this function by creating the following Access Basic function:

         Sub ShowInfo ()
            Dim a$, b$, c$, d$
   
            If GetWorkstationInfo(a$, b$, c$, d$) Then
               MsgBox a$ & " " & b$ & " " & c$ & " " & d$
            Else
               MsgBox "Unable to get information."
            End If
         End Sub
   
   

3. In the Immediate window, type the following, and the press ENTER:

         ShowInfo
   

REFERENCES

For an example of this article in Microsoft Access version 7.0, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q148835
   TITLE:      ACC: How to Retrieve Workgroup Information Under Win32