VB6转换为C#错误

现在我正在将一个VB6项目移植到C#上,并不断出现此错误。似乎无法在命名空间中修复它。

问题:

//Expected class, delegate, enum, interface, or struct
public string GetHostByAddress(long addr)
{
    dynamic phe = null;
    dynamic Ret = null;
    HOSTENT heDestHost = default(HOSTENT);
    dynamic hostname = null;

    phe = gethostbyaddr(addr, 4, PF_INET);
    if (phe) {
        MemCopy(heDestHost, phe, hostent_size);
        hostname == new String[256, 0];
        MemCopy(hostname, heDestHost.h_name, 256);
        GetHostByAddress == Strings.Left(hostname, Strings.InStr(hostname, Strings.Chr(0)) - 1);
    } else {
        GetHostByAddress = WSA_NoName;
    }
}

Public Function GetHostByAddress(ByVal addr As Long) As String

  Dim phe&, Ret&
  Dim heDestHost As HOSTENT
  Dim hostname&

    phe = gethostbyaddr(addr, 4, PF_INET)
    If phe Then
        MemCopy heDestHost, ByVal phe, hostent_size
        hostname = String$(256, 0)
        MemCopy ByVal hostname, ByVal heDestHost.h_name, 256
        GetHostByAddress = Left$(hostname, InStr(hostname, Chr$(0)) - 1)
      Else
        GetHostByAddress = WSA_NoName
    End If

End Function

不明白为什么它不起作用而感到沮丧。有什么建议吗?