Visual Basic

 <DllImport("mpr.dll", SetLastError:=False, CharSet:=CharSet.Auto)> _
Friend Shared Function WNetGetUniversalName( _
ByVal lpLocalPath As String, _
ByVal dwInfoLevel As Int32, _
ByVal lpBuffer As IntPtr, _
ByRef lpBufferSize As Int32) As Int32
 End Function

 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
     Dim bufSize As Int32 = 2000
     Dim bufPtr As IntPtr = Marshal.AllocHGlobal(bufSize)
     Dim sMapPath As String = "Z:\"
     Dim ret As Int32 = WNetGetUniversalName(sMapPath, 2, bufPtr, bufSize)
     If ret = 0 Then 'ERROR_SUCCESS
         Debug.WriteLine("This is a Mapped Network Drive " & ret)
     End If
     If ret = 1200 Then 'ERROR_BAD_DEVICE
         Debug.WriteLine("The specified device name is invalid. " & ret)
     End If
     If ret = 2250 Then 'ERROR_NOT_CONNECTED
         Debug.WriteLine("This network connection does not exist. " & ret)
     End If
     Marshal.FreeHGlobal(bufPtr)
 End Sub

' Retrieve the working rectangle from the Screen class
' using the PrimaryScreen and the WorkingArea properties.
Dim workingRectangle As System.Drawing.Rectangle = _
    Screen.PrimaryScreen.WorkingArea

' Set the size of the form slightly less than size of
' working rectangle.
Me.Size = New System.Drawing.Size(workingRectangle.Width - 10, _
    workingRectangle.Height - 10)

' Set the location so the entire form is visible.
Me.Location = New System.Drawing.Point(5, 5)

Public Function GetComboBoxIndex(hWnd As Long, SearchKey As String, Optional FindExactMatch As Boolean = True) As Integer

    'Parameters:
    ' hWnd - the handle to the ComboBox control.  Usage:  Combo1.hWnd
    ' SearchKey - item that you would like to search for.  Can be any string - case doesn't matter when searching
    ' Optional FindExactMatch - Default is True.  Pass False to find a partial match
    'Return:
    ' Returns the index of the found match.  If the match is not found, -1 is returned
    'Usage:
    ' Combo1.ListIndex = GetComboBoxIndex(Combo1.hWnd, "Test Item")
    ' Combo1.ListIndex = GetComboBoxIndex(Combo1.hWnd, "Test Item", False)
  
    If FindExactMatch Then
        GetComboBoxIndex = CInt(SendMessage(hWnd, CB_FINDSTRINGEXACT, -1, ByVal SearchKey))
    Else
        GetComboBoxIndex = CInt(SendMessage(hWnd, CB_FINDSTRING, -1, ByVal SearchKey))
    End If
    
End Function

Public Sub AutoFillCombobox(ByRef comboBox As comboBox, ByRef KeyAscii As Integer)

    Dim intIndex As Integer
    Dim intRemainder As Integer
    Dim strFullText As String
    Dim strPartialText As String
    
    If comboBox.Locked Then
        KeyAscii = 0
        Exit Sub
    End If
    
    If KeyAscii >= 33 And KeyAscii <= 126 Then
        comboBox.SelText = Chr(KeyAscii)
        strPartialText = comboBox.Text
        
        intIndex = GetComboBoxIndex(comboBox.hWnd, strPartialText, False)
        If intIndex > -1 Then
            strFullText = comboBox.List(intIndex)
            intRemainder = Len(strFullText) - Len(strPartialText)
            If intRemainder > 0 Then
                comboBox.SelStart = Len(comboBox.Text)
                comboBox.SelText = Right(strFullText, intRemainder)
                comboBox.SelStart = Len(strPartialText)
                comboBox.SelLength = Len(strFullText) - Len(strPartialText)
            End If
        End If
        
        KeyAscii = 0
    End If

End Sub

Public Function IsComboboxItemValid(ByRef comboBox As comboBox, Optional ByVal blnPrompt As Boolean = False, Optional ByRef Cancel As Boolean) As Boolean
    Dim intIndex As Integer
    intIndex = -1
    If IsComboboxItemListed(comboBox, intIndex) Then
        comboBox.ListIndex = intIndex
        IsComboboxItemValid = True
    Else
        IsComboboxItemValid = False
        Cancel = True
        If blnPrompt Then
            MsgBox "Item is not in the list." & vbCrLf & "Please select an item from the list.", vbInformation, "Item Not Available"
        End If
    End If
End Function