封装类：
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; public int dwHardwareOverrunErr; public int dwFramingErr; public int dwBufferOverrunErr; public int dwCompressionRatioIn; public int dwCompressionRatioOut; public int dwBps; public int dwConnectionDuration;}[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]public struct RasEntryName{ public int dwSize; //[MarshalAs(UnmanagedType.ByValTStr,SizeConst=(int)RasFieldSizeConstants.RAS_MaxEntryName + 1)] public string szEntryName; //#if WINVER5 // public int dwFlags; // [MarshalAs(UnmanagedType.ByValTStr,SizeConst=260+1)] // public string szPhonebookPath; //#endif}public class RAS{ [DllImport("Rasapi32.dll", EntryPoint = "RasEnumConnectionsA", SetLastError = true)] internal static extern int RasEnumConnections ( ref RASCONN lprasconn, // buffer to receive connections data ref int lpcb, // size in bytes of buffer ref int lpcConnections // number of connections written to buffer ); [DllImport("rasapi32.dll", CharSet = CharSet.Auto)] internal static extern uint RasGetConnectionStatistics( IntPtr hRasConn, // handle to the connection [In, Out]RasStats lpStatistics // buffer to receive statistics ); [DllImport("rasapi32.dll", CharSet = CharSet.Auto)] public extern static uint RasHangUp( IntPtr hrasconn // handle to the RAS connection to hang up ); [DllImport("rasapi32.dll", CharSet = CharSet.Auto)] public extern static uint RasEnumEntries( string reserved, // reserved, must be NULL string lpszPhonebook, // pointer to full path and // file name of phone-book file [In, Out]RasEntryName[] lprasentryname, // buffer to receive // phone-book entries ref int lpcb, // size in bytes of buffer out int lpcEntries // number of entries written // to buffer ); [DllImport("wininet.dll", CharSet = CharSet.Auto)] public extern static int InternetDial( IntPtr hwnd, [In]string lpszConnectoid, uint dwFlags, ref int lpdwConnection, uint dwReserved ); public RAS() { }}public enum DEL_CACHE_TYPE //要删除的类型。{ File,//表示internet临时文件 Cookie //表示Cookie}public class RASDisplay{ [DllImport("wininet.dll", CharSet = CharSet.Auto)] public static extern bool DeleteUrlCacheEntry( DEL_CACHE_TYPE type ); private string m_duration; private string m_ConnectionName; private string[] m_ConnectionNames; private double m_TX; private double m_RX; private bool m_connected; private IntPtr m_ConnectedRasHandle; RasStats status = new RasStats(); public RASDisplay() { m_connected = true; RAS lpras = new RAS(); RASCONN lprasConn = new RASCONN(); lprasConn.dwSize = Marshal.SizeOf(typeof(RASCONN)); lprasConn.hrasconn = IntPtr.Zero; int lpcb = 0; int lpcConnections = 0; int nRet = 0; lpcb = Marshal.SizeOf(typeof(RASCONN)); nRet = RAS.RasEnumConnections(ref lprasConn, ref lpcb, ref lpcConnections); if (nRet != 0) { m_connected = false; return; } if (lpcConnections > 0) { //for (int i = 0; i < lpcConnections; i++) //{ RasStats stats = new RasStats(); m_ConnectedRasHandle = lprasConn.hrasconn; RAS.RasGetConnectionStatistics(lprasConn.hrasconn, stats); m_ConnectionName = lprasConn.szEntryName; int Hours = 0; int Minutes = 0; int Seconds = 0; Hours = ((stats.dwConnectionDuration / 1000) / 3600); Minutes = ((stats.dwConnectionDuration / 1000) / 60) - (Hours * 60); Seconds = ((stats.dwConnectionDuration / 1000)) - (Minutes * 60) - (Hours * 3600); m_duration = Hours + " hours " + Minutes + " minutes " + Seconds + " secs"; m_TX = stats.dwBytesXmited; m_RX = stats.dwBytesRcved; //} } else { m_connected = false; } int lpNames = 1; int entryNameSize = 0; int lpSize = 0; RasEntryName[] names = null; entryNameSize = Marshal.SizeOf(typeof(RasEntryName)); lpSize = lpNames * entryNameSize; names = new RasEntryName[lpNames]; names[0].dwSize = entryNameSize; uint retval = RAS.RasEnumEntries(null, null, names, ref lpSize, out lpNames); //if we have more than one connection, we need to do it again if (lpNames > 1) { names = new RasEntryName[lpNames]; for (int i = 0; i < names.Length; i++) { names[i].dwSize = entryNameSize; } retval = RAS.RasEnumEntries(null, null, names, ref lpSize, out lpNames); } m_ConnectionNames = new string[names.Length]; if (lpNames > 0) { for (int i = 0; i < names.Length; i++) { m_ConnectionNames[i] = names[i].szEntryName; } } } public string Duration { get { return m_connected ? m_duration : ""; } } public string[] Connections { get { return m_ConnectionNames; } } public double BytesTransmitted { get { return m_connected ? m_TX : 0; } } public double BytesReceived { get { return m_connected ? m_RX : 0; } } public string ConnectionName { get { return m_connected ? m_ConnectionName : ""; } } public bool IsConnected { get { return m_connected; } } public int Connect(string Connection) { int temp = 0; uint INTERNET_AUTO_DIAL_UNATTENDED = 2; int retVal = RAS.InternetDial(IntPtr.Zero, Connection, INTERNET_AUTO_DIAL_UNATTENDED, ref temp, 0); return retVal; } public void Disconnect() { RAS.RasHangUp(m_ConnectedRasHandle); }}
调用方法：
RASDisplay ras = new RASDisplay();ras.Disconnect();//断开连接ras.Connect("ADSL");//重新拨号
注意：断开后连接时，如果不想出现确认对话框，请按下面的步骤进行设置：
1、右击“网上邻居”--属性；
2、在随后出现的“宽带连接”窗口中，右击宽带连接，单击“属性”；
3、在随后出现的属性对话框中，单击“选项”；
4、把随后出现的“提示名称、密码和证书等”前面的对号去掉，点“确定”退出；