vb里这句话是什么意思？ @_@

Question

关于红色lt_msg_send_clt 的部分

c#里没见过这种用法啊。。。。orz
请问，在c#里该怎么实现段代码 - =

　　Private Declare Function lt_msg_enter_clt Lib "ltws32.dll" (ByVal Host As String
, ByVal Service As String, ByVal program As String, ByRef error_no As Integer) As Integer


    Public Function CF_send(ByVal Buf As String, ByVal Buf_len As Short) As Short
        error_no = lt_msg_send_clt(m_handle, Buf, CInt(Buf_len))
        If error_no <> 0 Then
            CS_GetWinSockERR()
        End If
        CF_send = CShort(error_no)
    End Function

 
c#改写vb中，vb完全不会 (┬＿┬)

麻烦大家帮帮忙，谢谢了。。。