C#中一点按钮就弹出“拨号连接”的代码是什么啊？

ADSL自动拨号类,前提是在系统中已经有了一个宽带拨号连接
调用代码:
RASDisplay ras = new RASDisplay();
ras.Disconnect();//断线
ras.Connect("adsl");//拨号

using System;
using System.Runtime.InteropServices;
public struct RASCONN
{
public int dwSize;
public IntPtr hrasconn;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=257)]
public string szEntryName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=17)]
public string szDeviceType;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst=129)]
public string szDeviceName;
}

[StructLayout(LayoutKind.Sequential,CharSet=CharSet.Auto)]
public struct RasStats
{
public int dwSize;
public int dwBytesXmited;
public int dwBytesRcved;
public int dwFramesXmited;
public int dwFramesRcved;
public int dwCrcErr;
public int dwTimeoutErr;
public int dwAlignmentErr;
publ