如何自动连接网络和断开网络
我家用的是联通的宽带，
根据用户名和密码如何用代码实现连接网络和断开网络？
[解决办法]
http://blog.sina.com.cn/s/blog_4c55fd6101000bm4.html
Dim ras As New RASDisplay()
ras.Disconnect() '断线
ras.Connect("adsl") '拨号
Imports System.Runtime.InteropServicesPublic Structure RASCONN Public dwSize As Integer Public hrasconn As IntPtr <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=257)> _ Public szEntryName As String <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=17)> _ Public szDeviceType As String <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=129)> _ Public szDeviceName As StringEnd Structure<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _Public Structure RasStats Public dwSize As Integer Public dwBytesXmited As Integer Public dwBytesRcved As Integer Public dwFramesXmited As Integer Public dwFramesRcved As Integer Public dwCrcErr As Integer Public dwTimeoutErr As Integer Public dwAlignmentErr As Integer Public dwHardwareOverrunErr As Integer Public dwFramingErr As Integer Public dwBufferOverrunErr As Integer Public dwCompressionRatioIn As Integer Public dwCompressionRatioOut As Integer Public dwBps As Integer Public dwConnectionDuration As IntegerEnd Structure<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _Public Structure RasEntryName Public dwSize As Integer Public szEntryName As String End StructurePublic Class RAS <DllImport("Rasapi32.dll", EntryPoint:="RasEnumConnectionsA", SetLastError:=True)> _ Friend Shared Function RasEnumConnections(ByRef lprasconn As RASCONN, ByRef lpcb As Integer, ByRef lpcConnections As Integer) As Integer End Function <DllImport("rasapi32.dll", CharSet:=CharSet.Auto)> _ Friend Shared Function RasGetConnectionStatistics(ByVal hRasConn As IntPtr, <[In](), Out()> ByVal lpStatistics As RasStats) As UInteger End Function <DllImport("rasapi32.dll", CharSet:=CharSet.Auto)> _ Public Shared Function RasHangUp(ByVal hrasconn As IntPtr) As UInteger End Function <DllImport("rasapi32.dll", CharSet:=CharSet.Auto)> _ Public Shared Function RasEnumEntries(ByVal reserved As String, ByVal lpszPhonebook As String, <[In](), Out()> ByVal lprasentryname As RasEntryName(), ByRef lpcb As Integer, ByRef lpcEntries As Integer) As UInteger End Function <DllImport("wininet.dll", CharSet:=CharSet.Auto)> _ Public Shared Function InternetDial(ByVal hwnd As IntPtr, <[In]()> ByVal lpszConnectoid As String, ByVal dwFlags As UInteger, ByRef lpdwConnection As Integer, ByVal dwReserved As UInteger) As Integer End Function End ClassPublic Enum DEL_CACHE_TYPE '要删除的类型。 File '表示internet临时文件 Cookie '表示Cookie End EnumPublic Class RASDisplay <DllImport("wininet.dll", CharSet:=CharSet.Auto)> _ Public Shared Function DeleteUrlCacheEntry(ByVal type As DEL_CACHE_TYPE) As Boolean End Function Private m_duration As String Private m_ConnectionName As String Private m_ConnectionNames As String() Private m_TX As Double Private m_RX As Double Private m_connected As Boolean Private m_ConnectedRasHandle As IntPtr Private status As New RasStats() Public Sub New() m_connected = True Dim lpras As New RAS() Dim lprasConn As New RASCONN() lprasConn.dwSize = Marshal.SizeOf(GetType(RASCONN)) lprasConn.hrasconn = IntPtr.Zero Dim lpcb As Integer = 0 Dim lpcConnections As Integer = 0 Dim nRet As Integer = 0 lpcb = Marshal.SizeOf(GetType(RASCONN)) nRet = RAS.RasEnumConnections(lprasConn, lpcb, lpcConnections) If nRet <> 0 Then m_connected = False Return End If If lpcConnections > 0 Then Dim stats As New RasStats() m_ConnectedRasHandle = lprasConn.hrasconn RAS.RasGetConnectionStatistics(lprasConn.hrasconn, stats) m_ConnectionName = lprasConn.szEntryName Dim Hours As Integer = 0 Dim Minutes As Integer = 0 Dim Seconds As Integer = 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 End If Dim lpNames As Integer = 1 Dim entryNameSize As Integer = 0 Dim lpSize As Integer = 0 Dim names As RasEntryName() = Nothing entryNameSize = Marshal.SizeOf(GetType(RasEntryName)) lpSize = lpNames * entryNameSize names = New RasEntryName(lpNames - 1) {} names(0).dwSize = entryNameSize Dim retval As UInteger = RAS.RasEnumEntries(Nothing, Nothing, names, lpSize, lpNames) If lpNames > 1 Then names = New RasEntryName(lpNames - 1) {} For i As Integer = 0 To names.Length - 1 names(i).dwSize = entryNameSize Next retval = RAS.RasEnumEntries(Nothing, Nothing, names, lpSize, lpNames) End If m_ConnectionNames = New String(names.Length - 1) {} If lpNames > 0 Then For i As Integer = 0 To names.Length - 1 m_ConnectionNames(i) = names(i).szEntryName Next End If End Sub Public ReadOnly Property Duration() As String Get Return If(m_connected, m_duration, "") End Get End Property Public ReadOnly Property Connections() As String() Get Return m_ConnectionNames End Get End Property Public ReadOnly Property BytesTransmitted() As Double Get Return If(m_connected, m_TX, 0) End Get End Property Public ReadOnly Property BytesReceived() As Double Get Return If(m_connected, m_RX, 0) End Get End Property Public ReadOnly Property ConnectionName() As String Get Return If(m_connected, m_ConnectionName, "") End Get End Property Public ReadOnly Property IsConnected() As Boolean Get Return m_connected End Get End Property Public Function Connect(ByVal Connection As String) As Integer Dim temp As Integer = 0 Dim INTERNET_AUTO_DIAL_UNATTENDED As UInteger = 2 Dim retVal As Integer = RAS.InternetDial(IntPtr.Zero, Connection, INTERNET_AUTO_DIAL_UNATTENDED, temp, 0) Return retVal End Function Public Sub Disconnect() RAS.RasHangUp(m_ConnectedRasHandle) End SubEnd Class