static extern void CoDisconnectObject(

    Connect =   2,

    Connect =   2,

static extern IntPtr WinHttpConnect(IntPtr hSession,

Declare Function WinHttpConnect Lib "winhttp.dll" (ByVal hSession As IntPtr, ByVal pswzServerName As String, ByVal nServerPort As Short, ByVal dwReserved As Integer) As IntPtr

            IntPtr hConnect,

            IntPtr hConnect,

Declare Function WinHttpOpenRequest Lib "winhttp.dll" (ByVal hConnect As IntPtr, ByVal pwszVerb As String, ByVal pwszObjectName As String, ByVal pwszVersion As String, ByVal pwszReferrer As String, ByRef ppwszAcceptTypes As Byte(), ByVal dwFlags As Integer) As IntPtr

            IntPtr hConnect,

Declare Function WinHttpOpenRequest Lib "winhttp.dll" (ByVal hConnect As IntPtr, ByVal pwszVerb As String, ByVal pwszObjectName As String, ByVal pwszVersion As String, ByVal pwszReferrer As String, ByRef ppwszAcceptTypes As Byte(), ByVal dwFlags As Integer) As IntPtr

            int dwConnectTimeout,

Declare Function WinHttpSetTimeouts Lib "winhttp.dll" (ByVal hInternet As IntPtr, ByVal dwResolveTimeout As Integer, ByVal dwConnectTimeout As Integer, ByVal dwSendTimeout As Integer, ByVal dwReceiveTimeout As Integer) As Boolean

    if (MessageBox.Show(this, "Are you sure you want to close this connection?" == DialogResult.Yes))

    If MsgBox("Are you sure you want to disconnect this resource?", MsgBoxStyle.YesNo) = MsgBoxResult.Yes Then

lpAccount - (in) Pointer to a constant string that specifies an account name to use when connecting to the domain controller. If this parameter is NULL, the caller's context is used.

lpPassword - (in) If the lpAccount parameter specifies an account name, this parameter must point to the password to use when connecting to the domain controller. Otherwise, this parameter must be NULL.

    public int AutoDisconnectMinutes;

    ''' <param name="UncClientName">[in] Pointer to a string that specifies the computer name of the client to disconnect. If UncClientName is NULL, then all the sessions of the user identified by the username parameter will be deleted on the server specified by servername.</param>

        /// Unable to contact resource. Connection timed out.

        /// No available network connection to make call.

lpAccount - (in) Pointer to a constant string that specifies the account name to use when connecting to the domain controller. The string must specify either a domain NetBIOS name and user account (for example, "REDMOND\user") or the user principal name (UPN) of the user in the form of an Internet-style login name (for example, "someone@example.com"). If this parameter is NULL, the caller's context is used.

lpPassword - (in) If the lpAccount parameter specifies an account name, this parameter must point to the password to use when connecting to the domain controller. Otherwise, this parameter must be NULL.

You can also use the WNetAddConnection2 and WNetAddConnection3 functions to redirect a local device to a network resource. Connections added by NetUseAdd are not shown in the Explorer. You should use one of the WNetAddConnection methods to make the networkdrive visible in the explorer.

You can also use the WNetCancelConnection2 function to terminate a network connection.

            // now step through all network shares and check if we have already a connection to the server

        //  Connection/Session counts

        public int Reconnects;

        public int CoreConnects;

        public int Lanman20Connects;

        public int Lanman21Connects;

        public int LanmanNtConnects;

        public int ServerDisconnects;

static extern IntPtr DdeConnect(uint idInst, IntPtr hszService,

IntPtr handle = DdeConnect(instanceId, serviceHandle, topicHandle, IntPtr.Zero);

static extern IntPtr DdeReconnect(IntPtr hConv);

Add per machine printer connection (the connection will be propagated to the user upon logon):

Delete per machine printer connection (the connection will be deleted upon user logon):

hConnect (in) A handle returned from a call to InternetConnect.

fExpectResponse (in) A Boolean value that indicates whether the application expects a data connection to be established by the FTP server. This must be set to TRUE if a data connection is expected, or FALSE otherwise.

Dim ret As Boolean = FTPCommandA(ConnectionHandle, False, 0, sCommand, IntPtr.Zero, IntPtr.Zero)

static extern bool FtpCreateDirectory(IntPtr hConnect, string lpszDirectory);

  Private Shared Function FtpCreateDirectory(ByVal hConnect As IntPtr, ByVal lpszDirectory As String) As Boolean

static extern bool FtpDeleteFile(IntPtr hConnect, string fileName);

   (ByVal hConnect As IntPtr, ByVal fileName As String) _

   static extern IntPtr FtpFindFirstFile(IntPtr hConnect,

   (ByVal hConnect As IntPtr, ByVal searchFile As String, _

static extern bool FtpGetCurrentDirectory(IntPtr hConnect,

   (ByVal hConnect As IntPtr, ByVal directory As StringBuilder, ByRef bufferLength As Integer) _

' and Me.hINetConn is an IntPtr opened by InternetConnect

static extern bool FtpGetFile(IntPtr hConnect, string remoteFile,

Declare Function FtpGetFile Lib "wininet.dll" (ByVal hConnect As IntPtr, _

    [DllImport("wininet.dll", EntryPoint = "InternetConnectW", CharSet = CharSet.Auto, SetLastError = true)]

    private static extern IntPtr InternetConnectW(

    public void Connect()

        ftpHandle = InternetConnectW(internetHandle, FTPSite,

    public void Disconnect()

        Connect();

        Connect();

        Disconnect();

static extern bool FtpPutFile(IntPtr hConnect, string lpszLocalFile, string lpszNewRemoteFile, int dwFlags, IntPtr dwContext);

Call InternetOpen() and InternetConnect() to get a valid hConnect handle.

                (ByVal hConnect As Integer, ByVal lpszExisting As String, _

Call InternetOpen() and InternetConnect() to get a valid hConnect handle.

static extern bool FtpSetCurrentDirectory(IntPtr hFtpConnection, string lpszDirectory);

Declare Function FtpSetCurrentDirectory Lib "wininet.dll" Alias "FtpSetCurrentDirectoryA" (ByVal hConnect As IntPtr, ByVal lpszDirectory As String) As Boolean

    IntPtr hConnect,

  __in  HINTERNET hConnect,

static extern int InternetAttemptConnect(int dwReserved);

Public Declare Function InternetAttemptConnect Lib "wininet" (Optional ByVal dwReserved As Long = 0) As Long

If the computer is already connected, the function may hang.

  ' This function tries to connect to the internet. If it works, it returns True,

  Private Declare Function InternetAttemptConnect Lib "wininet" (Optional ByVal dwReserved As Integer = 0) As Integer

  Public Function ConnectToInternet() As Boolean

    If InternetAttemptConnect(0) = 0 Then

static extern bool InternetCheckConnection(string lpszUrl, int dwFlags, int dwReserved);

Declare Function InternetCheckConnection Lib "wininet.dll" (ByVal lpszUrl As String, ByVal dwFlags As Integer, ByVal dwReserved As Integer) As Boolean

private static extern bool InternetCheckConnection(string lpszUrl, int dwFlags, int dwReserved);

bool connectivity;

if (InternetCheckConnection("http://www.google.com/", 1, 0))

     connectivity = true;

    * Returns a valid handle to the FTP, Gopher, or HTTP session if the connection is successful, or NULL otherwise. To get extended error information, call GetLastError. An application can also use InternetGetLastResponseInfo to determine why access to the service was denied.

static extern IntPtr InternetConnect(

Declare Auto Function InternetConnect Lib "wininet.dll" (

    Number of the TCP/IP port on the server to connect to. Can be one of the values in the following list. If this parameter is set to INTERNET_INVALID_PORT_NUMBER, the function uses the default port for the specified service. These values do not cause the function to use this protocol. The value sets the port to be used. A flag must be used to set the service.

    INTERNET_SERVICE_FTP     INTERNET_CONNECT_FLAG_PASSIVE (Use passive mode in all data connections for this FTP session.)

The InternetConnect function is required before communicating with any Internet service.

Having a connect function for all protocols, even those that do not use persistent connections, lets an application communicate common information about several requests using a single function call. In addition, this allows for future versions of Internet protocols that do not require a connection to be established for every client request.

For FTP sites, InternetConnect actually establishes a connection with the server; for others, such as Gopher, the actual connection is not established until the application requests a specific transaction.

For maximum efficiency, applications using the Gopher and HTTP protocols should try to minimize calls to InternetConnect and avoid calling this function for every transaction requested by the user. One way to accomplish this is to keep a small cache of handles returned from InternetConnect; when the user makes a request to a previously accessed server, that session handle is still available.

For FTP connections, if lpszUsername is NULL, InternetConnect sends the string "anonymous" as the user name. If lpszPassword is NULL, InternetConnect attempts to use the user's e-mail name as the password.

To close the handle returned from InternetConnect, the application should call InternetCloseHandle. This function disconnects the client from the server and frees all resources associated with the connection.

private static extern Int32 InternetDial(IntPtr hwndParent, string lpszConnectoid, Int32 dwFlags, ref Int32 lpdwConnection, Int32 dwReserved);

int nResult = InternetDial(IntPtr.Zero ,"Your connection",(int)InternetDialFlags.INTERNET_DIAL_UNATTENDED ,ref nConnection , 0);

///     Retrieves the connected state of the local system.

///     C++ ( lpdwFlags [out]. Type: LPDWORD )<br />Pointer to a variable that receives the connection description. This

///         <term>Internet Connection State Possible Flags</term>

///         <term>INTERNET_CONNECTION_CONFIGURED (0x40)</term>

///         Local system has a valid connection to the Internet, but it might or might not be currently

///         connected.

///         <term>INTERNET_CONNECTION_LAN (0x02)</term>

///         <description>Local system uses a local area network to connect to the Internet.</description>

///         <term>INTERNET_CONNECTION_MODEM (0x01)</term>

///         <description>Local system uses a modem to connect to the Internet.</description>

///         <term>INTERNET_CONNECTION_MODEM_BUSY (0x08)</term>

///         <term>INTERNET_CONNECTION_OFFLINE (0x20)</term>

///         <term>INTERNET_CONNECTION_PROXY (0x04)</term>

///         <description>Local system uses a proxy server to connect to the Internet.</description>

///     <c>true</c> if there is an active modem or a LAN Internet connection, <c>false</c> if there is no Internet

///     connection, or if all possible Internet connections are not currently active.

///     A return value of TRUE from InternetGetConnectedState indicates that at least one connection to the Internet is

///     available. It does not guarantee that a connection to a specific host can be established. Applications should

///     always check for errors returned from API calls that connect to a server. InternetCheckConnection can be called to

///     determine if a connection to a specific destination can be established.

///     <br />A return value of TRUE indicates that either the modem connection is active, or a LAN connection is active

///     is connected.If FALSE is returned, the INTERNET_CONNECTION_CONFIGURED flag may be set to indicate that autodial is

extern static bool InternetGetConnectedState(out int lpdwFlags, int dwReserved);

enum ConnectionStates

  Private Declare Function InternetGetConnectedState Lib "wininet.dll" _

Private Enum ConnectionStates

InternetGetConnectedStateFlags

   private static extern bool InternetGetConnectedState(out int lpdwFlags, int dwReserved);

    bool isConnected = InternetGetConnectedState(out flags, 0);

    Console.WriteLine(string.Format("Is connected :{0} Flags:{1}", isConnected, flags));

Function Get_InternetConnectedState(ByRef p_lngFlags As Long, Optional ByRef p_return_str As String = "") As Boolean

      Get_InternetConnectedState = False

      If InternetGetConnectedState(lngFlags, 0) Then

     'connected.

     If lngFlags And ConnectionStates.LAN Then

        'LAN connection.

        p_return_str = "LAN connection."

     ElseIf lngFlags And ConnectionStates.Modem Then

        'Modem connection.

        p_return_str = "Modem connection."

     ElseIf lngFlags And ConnectionStates.Proxy Then

        'Proxy connection.

        p_return_str = "Proxy connection."

     Get_InternetConnectedState = True

     'not connected.

     p_return_str = "Not connected."

     Get_InternetConnectedState = False

Direct Link: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wininet/wininet/internetgetconnectedstate.asp

extern static int InternetHangUp(int Connection, int ReservedValue);

  sAgent can be any string, it is just to identify the connection

    /// Connection name to set/query options

    public IntPtr szConnection;

            CSIDL_CONNECTIONS           = 0x0031,    // Network and Dial-up Connections

        /// The computer has disconnected from a server.

        /// <i>dwItem1</i> contains the server from which the computer was disconnected.

        SHCNE_SERVERDISCONNECT = 0x00004000,

    ' The computer has disconnected from a server.

    ' <i>dwItem1</i> contains the server from which the computer was disconnected.

    SHCNE_SERVERDISCONNECT = &H4000

        SEE_MASK_CONNECTNETDRV = 0x00000080,  

            FOF_NO_CONNECTED_ELEMENTS = 0x2000,  // don't operate on connected elements.

        public bool FOF_NO_CONNECTED_ELEMENTS = false;

                if ( this.FOF_NO_CONNECTED_ELEMENTS )

                    ReturnValue |= (ushort)FILEOP_FLAGS_ENUM.FOF_NO_CONNECTED_ELEMENTS;

        CSIDL_CONNECTIONS         = 0x0031,    // Network and Dial-up Connections

    public static readonly Guid ConnectionsFolder = new Guid( "6F0CD92B-2E97-45D1-88FF-B0D186B8DEDD" );

    CONNECTIONS = &H31

        CSIDL_CONNECTIONS       = 0x0031,    // Network and Dial-up Connections

    public static Guid ConnectionsFolder = new Guid("6F0CD92B-2E97-45D1-88FF-B0D186B8DEDD");

            throw new Exception(String.Format("Error connecting to Service Control Manager. Error provided was: 0x{0:X}", Marshal.GetLastWin32Error()));

            throw new Exception(String.Format("Error connecting to Service Control Manager. Error provided was: 0x{0:X}", Marshal.GetLastWin32Error()));

        SC_MANAGER_CONNECT     = 0x00001,

            SC_MANAGER_CONNECT |

      private enum ServiceControlManagerType { SC_MANAGER_CONNECT = 0x1, SC_MANAGER_CREATE_SERVICE = 0x2, SC_MANAGER_ENUMERATE_SERVICE = 0x4, SC_MANAGER_LOCK = 0x8, SC_MANAGER_QUERY_LOCK_STATUS = 0x10, SC_MANAGER_MODIFY_BOOT_CONFIG = 0x20, SC_MANAGER_ALL_ACCESS = STANDARD_RIGHTS_REQUIRED | SC_MANAGER_CONNECT | SC_MANAGER_CREATE_SERVICE | SC_MANAGER_ENUMERATE_SERVICE | SC_MANAGER_LOCK | SC_MANAGER_QUERY_LOCK_STATUS | SC_MANAGER_MODIFY_BOOT_CONFIG }

    SHTDN_REASON_MINOR_NETWORK_CONNECTIVITY = 0x00000014,

    SHTDN_REASON_MINOR_NETWORK_CONNECTIVITY = &H14UI

    SHTDN_REASON_MINOR_NETWORK_CONNECTIVITY = 0x00000014,

    SHTDN_REASON_MINOR_NETWORK_CONNECTIVITY = &H14UI