C# WinApp ถ้ามี .dll ที่ไม่สารมารถ Add ref ได้เราจะใช้งาน method ข้างในยังไงรึครับ

Imports System.Net

Public Class SendARP
    Declare Function SendARP Lib "iphlpapi.dll" (ByVal DestIP As UInt32, ByVal SrcIP As UInt32, ByVal pMacAddr As Byte(), ByRef PhyAddrLen As Integer) As Integer

    Sub New()
    End Sub

    'http://www.pinvoke.net/default.aspx/iphlpapi.sendarp
    'Please do not use the IPAddress.Address property
    'This API is now obsolete. --> http://msdn.microsoft.com/en-us/library/system.net.ipaddress.address.aspx
    'to get the IP in Integer mode use
    Public Shared Function GetMacAddress(IPAddress As String) As String
        'Dim dst As IPAddress = System.Net.IPAddress.Parse(IPAddress)
        Dim intAddress As Integer = BitConverter.ToInt32(System.Net.IPAddress.Parse(IPAddress).GetAddressBytes(), 0)
        Dim macAddr As Byte() = New Byte(5) {}
        Dim macAddrLen As UInteger = CUInt(macAddr.Length)
        If SendARP(intAddress, 0, macAddr, macAddrLen) <> 0 Then
            Throw New InvalidOperationException("SendARP failed.")
        End If
        Dim str As String() = New String(CInt(macAddrLen) - 1) {}
        For i As Integer = 0 To macAddrLen - 1
            str(i) = macAddr(i).ToString("x2").ToUpper()
        Next
        Return String.Join("-", str)
    End Function
End Class