Visual Basic Tips

Determining The Computer's Host Name

This code was taken from the Microsoft site (based on Q160215) and then tidied up a little bit and then made into a simple class. All it does is present a property called .GetHostName which returns the computer's host name.

The error handling in this example has been reduced to a minimum in order to show the basic functionality.

Calling this routine is easy. If the class was called, for example, clsHostInformation, then the calling code would look like this:

  Dim oHost As clsHostInformation
  

  Set oHost = New clsHostInformation
  MsgBox oHost.HostName
  Set oHost = Nothing

The whole of the class is as follows:

Option Explicit


  Private Const WS_VERSION_REQD = &H101
  Private Const WS_VERSION_MAJOR = WS_VERSION_REQD \ &H100 And &HFF&
  Private Const WS_VERSION_MINOR = WS_VERSION_REQD And &HFF&
  Private Const MIN_SOCKETS_REQD = 1
  Private Const SOCKET_ERROR = -1
  Private Const WSADescription_Len = 256
  Private Const WSASYS_Status_Len = 128
  
  
  Private Type WSADATA
    wversion As Integer
    wHighVersion As Integer
    szDescription(0 To WSADescription_Len) As Byte
    szSystemStatus(0 To WSASYS_Status_Len) As Byte
    iMaxSockets As Integer
    iMaxUdpDg As Integer
    lpszVendorInfo As Long
  End Type
  
  Private Declare Function WSAGetLastError Lib "WSOCK32.DLL" () As Long
  Private Declare Function WSAStartup Lib "WSOCK32.DLL" (ByVal wVersionRequired As Integer, lpWSAData As WSADATA) As Long
  Private Declare Function WSACleanup Lib "WSOCK32.DLL" () As Long
  
  Private Declare Function GetHostName Lib "WSOCK32.DLL" Alias "gethostname" (ByVal HostName As String, ByVal HostLen As Long) As Long
  
  
  Private m_sHostName As String
'
'

Private Sub Class_Initialize()

  SocketsInitialize
  DetermineHostName
  SocketsCleanup
  
End Sub


Private Sub Class_Terminate()
  
  SocketsCleanup
  
End Sub


Public Property Get HostName() As String

  HostName = m_sHostName

End Property


Private Sub SocketsInitialize()

  Dim WSAD As WSADATA
  Dim nReturnCode As Long

  nReturnCode = WSAStartup(WS_VERSION_REQD, WSAD)

End Sub


Private Sub SocketsCleanup()

  Dim nReturnCode As Long

  On Error Resume Next
  nReturnCode = WSACleanup()

End Sub



Private Sub DetermineHostName()
   
  Dim sHostName As String * 256
  
  
  If GetHostName(sHostName, 256) = SOCKET_ERROR Then
    m_sHostName = ""
  Else
    m_sHostName = Left(sHostName, InStr(1, sHostName, Chr$(0), vbBinaryCompare) - 1)
  End If

End Sub

Updates

If there are any suggestions for updates then please drop me a mail at [email protected].