How do I work with dial-up (RAS) connections in Windows using C#/.NET?

Question

I need to be able to connect, disconnect, and re-connect a dial-up networking connection in a C# .NET Framework application. Creating the connection in the phone-book might also be useful/necessary.

Are there any classes or libraries written for C# or .NET out there that wrap all this functionality nicely for me? Anyone have some code they would be willing to share?

Note: Application is unattended, like a Kiosk, and thus requiring user action is unacceptable.

Answer 1

This is cut out from a couple different classes (some code omitted for possible privacy issues) so it may not compile with a straight copy. Hope it helps!

using System.Runtime.InteropServices;

[DllImport("wininet.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public extern static bool InternetGetConnectedState(
    out int connectionDescription,
    int reservedValue);

[DllImport("wininet.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.I4)]
public static extern int InternetAttemptConnect(int dwReserved);

public sealed class InternetConnection
{
    private InternetConnection()
    { }

    public static bool IsConnected()
    {
        int connectionDescription = 0;

        return InternetGetConnectedState(out connectionDescription, 0);
    }

    public static int Connect()
    {
        return InternetAttemptConnect(0);
    }
}

Answer 2

One way to do this is through Interop around RAS. RasDialDlg() can be used to open a dial-up networking connection without displaying the dialog box. Use RasHangUp() to disconnect.

RasEnumConnections() can be used to list available connections.

The dll is Rasapi32.dll - headers are in ras.h and raserror.h

Answer 3

Check out the DotRas project on CodePlex.com, it has the entire API completed.

http://www.codeplex.com/DotRas

Answer 4

using System;
using System.ComponentModel;
using System.Runtime.InteropServices;

namespace MenelGameAuto.Internet
{
    class RAS
    {
        #region <Fields>

        private int rasConnectionsAmount; // ilość struktur typu RASCONN
        #endregion

        [DllImport("wininet.dll", CharSet = CharSet.Auto)]
        static extern bool InternetGetConnectedState(
            ref int lpdwFlags,
            int dwReserved);

        const int MAX_PATH = 260;
        const int RAS_MaxDeviceType = 16;
        const int RAS_MaxPhoneNumber = 128;
        const int RAS_MaxEntryName = 256;
        const int RAS_MaxDeviceName = 128;

        const int RAS_Connected = 0x2000;

        /// <summary>
        /// Wykazuje wszystkie połączenia RAS.
        /// </summary>
        [DllImport("rasapi32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        private static extern int RasEnumConnections([In, Out] RASCONN[] lprasconn, ref int lpcb,ref int lpcConnections);

        [DllImport("rasapi32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern uint RasHangUp(IntPtr hRasConn);

        [DllImport("RASAPI32", SetLastError = true, CharSet = CharSet.Auto)]
        static extern int RasGetConnectStatus(IntPtr hrasconn, ref RASCONNSTATUS lprasconnstatus);

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        struct RASCONN
        {
            public int dwSize;
            public IntPtr hrasconn;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxEntryName + 1)]
            public string szEntryName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxDeviceType + 1)]
            public string szDeviceType;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxDeviceName + 1)]
            public string szDeviceName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_PATH)]
            public string szPhonebook;
            public int dwSubEntry;
        }

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        struct RASCONNSTATUS
        {
            public int dwSize;
            public int rasconnstate;
            public int dwError;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxDeviceType + 1)]
            public string szDeviceType;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxDeviceName + 1)]
            public string szDeviceName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxPhoneNumber + 1)]
            public string szPhoneNumber;
        }


        /// <summary>
        /// Pobranie wszystkich połączeń RAS.
        /// </summary>
        /// <returns>Struktury połączeń RAS</returns>
        private RASCONN[] GetRasConnections()
        {
            // Stworzenie tablicy, którą później należy przekazać funkcjom
            int rasEnumReturn;
            RASCONN[] rasconnStructs = new RASCONN[256];
            rasconnStructs.Initialize(); // inicjalizacja wszystkich pól struktury
            rasconnStructs[0].dwSize = Marshal.SizeOf(typeof(RASCONN)); // inicjalizacja pierwszego pola pierwszej struktury na wartość wielkości tej struktury
            int sizeOfRasconnStruct = rasconnStructs[0].dwSize * rasconnStructs.Length; // wielkość pojedynczej struktury * ilosc

            // Wywołanie RasEnumConnections do zdobycia wszystkich aktywnych połączeń RAS
            rasEnumReturn = RasEnumConnections(rasconnStructs, ref sizeOfRasconnStruct, ref rasConnectionsAmount);

            // jeżeli RasEnumConnections nie zwróciło ERROR_SUCCESS
            if (rasEnumReturn != 0) throw new Win32Exception(rasEnumReturn);
            return rasconnStructs;
        }

        /// <summary>
        /// Rozłącza internet.
        /// </summary>
        public void Disconnect()
        {
            RASCONN[] rasStructs = GetRasConnections();

            // Przejście przez każdą strukturę RASCONN
            for (int i = 0; i < rasConnectionsAmount; i++)
            {
                // Pobranie pojedynczej struktury
                RASCONN rStruct = rasStructs[i];

                // Jeżeli uchwyt do połączenia wynosi 0, to brak połączenia
                if (rStruct.hrasconn == IntPtr.Zero) continue; // i następna struktura...

                // Rozłączenie...
                RasHangUp(rStruct.hrasconn);
            }
        }

        public void Connect()
        {
            // TODO
        }

        public bool IsConnected()
        {
            RASCONN[] rasStructs = GetRasConnections();

            RASCONNSTATUS rasConnStatus = new RASCONNSTATUS();
            rasConnStatus.dwSize = Marshal.SizeOf(typeof(RASCONNSTATUS));

            for (int i = 0; i < rasConnectionsAmount; ++i)
            {
                // Pobranie pojedynczej struktury
                RASCONN rStruct = rasStructs[i];

                int statusResult = RasGetConnectStatus(rStruct.hrasconn, ref rasConnStatus);
                if (statusResult != 0) throw new Win32Exception(statusResult);
                if(rasConnStatus.rasconnstate == RAS_Connected) return true;
            }
            return false;
        }
    }
}