C# Definition:

[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Ansi)]
public struct IP_ADAPTER_INFO
{
    public IntPtr Next;
    public Int32 ComboIndex;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst=MAX_ADAPTER_NAME_LENGTH + 4)]
      public string AdapterName;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst=MAX_ADAPTER_DESCRIPTION_LENGTH + 4)]
      public string AdapterDescription;
    public UInt32 AddressLength;
    [MarshalAs(UnmanagedType.ByValArray, SizeConst=MAX_ADAPTER_ADDRESS_LENGTH)]
      public byte [] Address;
    public Int32 Index;
    public UInt32 Type;
    public UInt32 DhcpEnabled;
    public IntPtr CurrentIpAddress;
    public IP_ADDR_STRING IpAddressList;
    public IP_ADDR_STRING GatewayList;
    public IP_ADDR_STRING DhcpServer;
    public bool HaveWins;
    public IP_ADDR_STRING PrimaryWinsServer;
    public IP_ADDR_STRING SecondaryWinsServer;
    public Int32 LeaseObtained;
    public Int32 LeaseExpires;
}

VB Definition:

    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _
    Private Structure IP_ADAPTER_INFO
    Dim [Next] As IntPtr
    Dim ComboIndex As Int32
    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=(MAX_ADAPTER_NAME_LENGTH + 4))> _
        Dim AdapterName As String
    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=(MAX_ADAPTER_DESCRIPTION_LENGTH + 4))> _
        Dim Description As String
    Dim AddressLength As UInt32
    <MarshalAs(UnmanagedType.ByValArray, SizeConst:=(MAX_ADAPTER_ADDRESS_LENGTH))> _
        Dim Address() As Byte
    Dim Index As Int32
    Dim Type As UInt32
    Dim DhcpEnabled As UInt32
    Dim CurrentIpAddress As IP_ADDRESS_STRING
    Dim IpAddressList As IP_ADDRESS_STRING
    Dim GatewayList As IP_ADDRESS_STRING
    Dim DhcpServer As IP_ADDRESS_STRING
    Dim HaveWins As Boolean
    Dim PrimaryWinsServer As IP_ADDRESS_STRING
    Dim SecondaryWinsServer As IP_ADDRESS_STRING
    Dim LeaseObtained As Int32
    Dim LeaseExpires As Int32
    End Structure

User-Defined Field Types:

None.

Notes:

Failed on CharSet:=CharSet.Auto on WinXP: -> CharSet:=CharSet.ANSI worked