C# 实现ADSL自动断网和拨号（适用于拨号用户）

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；