Microsoft KB Archive/198896

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HOWTO: List Servers in 32-bit Visual Basic Using NetServerEnum

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Q198896

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The information in this article applies to:


 * Microsoft Windows NT Server version 4.0
 * Microsoft Windows NT Workstation version 4.0
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Server
 * Microsoft Windows 2000 Professional

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SUMMARY
This article includes a sample which demonstrates how to enumerate all servers of the specified type that are visible in the specified domain in a 32-bit Visual Basic application using NetServerEnum.

Note that the 32-bit version of NetServerEnum is only supported in Windows NT. The function uses UNICODE for its string parameters.

MORE INFORMATION
Note when calling C functions in Visual Basic (VB), the relevant constants, structures(types), and functional prototypes have to be redefined or declared. This example shows how to use NetServerEnum at level 101 to enumerate all types of visible servers in a domain. Therefore, you must define the filtering flag SV_TYPE_SERVER and the structure SERVER_INFO_101 based on the C header file Lmserver.h. You also have to declare the prototypes for NetServerEnum and the memory management functions such as NetApiBufferFree, RtlMoveMemory, and lstrcpyW.

The sample application contains only two buttons, Command1 and Command2. Command1 is for executing NetServerEnum and Command2 is used to exit the application.

  Option Explicit

' General definitions Const ERROR_SUCCESS = 0 Const ERROR_MORE_DATA = 234 Const SV_TYPE_SERVER = &H2  'Server type mask, all types of servers Const SIZE_SI_101 = 24

Private Type SERVER_INFO_101 dwPlatformId As Long lpszServerName As Long dwVersionMajor As Long dwVersionMinor As Long dwType As Long lpszComment As Long End Type

Private Declare Function NetServerEnum Lib "netapi32.dll" ( _     ByVal servername As String, _      ByVal level As Long, _      buffer As Long, _      ByVal prefmaxlen As Long, _      entriesread As Long, _      totalentries As Long, _      ByVal servertype As Long, _      ByVal domain As String, _      resumehandle As Long) As Long

Private Declare Function NetApiBufferFree Lib "netapi32.dll" ( _     BufPtr As Any) As Long Private Declare Sub RtlMoveMemory Lib "KERNEL32" ( _     hpvDest As Any, ByVal hpvSource As Long, ByVal cbCopy As Long) Private Declare Function lstrcpyW Lib "KERNEL32" ( _     ByVal lpszDest As String, ByVal lpszSrc As Long) As Long

Private Function PointerToString(lpszString As Long) As String Dim lpszStr1 As String, lpszStr2 As String, nRes As Long lpszStr1 = String(1000, "*") nRes = lstrcpyW(lpszStr1, lpszString) lpszStr2 = (StrConv(lpszStr1, vbFromUnicode)) PointerToString = Left(lpszStr2, InStr(lpszStr2, Chr$(0)) - 1) End Function

Private Sub Command1_Click Dim pszTemp As String, pszServer As String, pszDomain As String Dim nLevel As Long, i As Long, BufPtr As Long, TempBufPtr As Long Dim nPrefMaxLen As Long, nEntriesRead As Long, nTotalEntries As Long Dim nServerType As Long, nResumeHandle As Long, nRes As Long Dim ServerInfo As SERVER_INFO_101

' Get the server name. It can be a null string pszTemp = Chr(0) pszTemp = InputBox("Enter server name:", "Server Name") If Len(pszTemp) = 0 Then pszServer = vbNullString Else pszServer = StrConv(pszTemp, vbUnicode) End If

' Get the domain name. It can be a null string pszTemp = Chr(0) pszTemp = InputBox("Enter domain name:", "Domain Name") If Len(pszTemp) = 0 Then pszDomain = vbNullString Else pszDomain = StrConv(pszTemp, vbUnicode) End If

nLevel = 101 BufPtr = 0 nPrefMaxLen = &HFFFFFFFF nEntriesRead = 0 nTotalEntries = 0 nServerType = SV_TYPE_SERVER nResumeHandle = 0

Do        nRes = NetServerEnum(pszServer, nLevel, BufPtr, _                         nPrefMaxLen, nEntriesRead, nTotalEntries, _                         nServerType, pszDomain, nResumeHandle) If ((nRes = ERROR_SUCCESS) Or (nRes = ERROR_MORE_DATA)) And _ (nEntriesRead > 0) Then TempBufPtr = BufPtr For i = 1 To nEntriesRead RtlMoveMemory ServerInfo, TempBufPtr, SIZE_SI_101 Debug.Print PointerToString(ServerInfo.lpszServerName) TempBufPtr = TempBufPtr + SIZE_SI_101 Next i        Else MsgBox "NetServerEnum failed: " & nRes End If        NetApiBufferFree (BufPtr) Loop While nEntriesRead < nTotalEntries

End Sub

Private Sub Command2_Click Unload Me  End Sub