C# Signature:

[DllImport("iphlpapi.dll", SetLastError=true)]
static extern uint GetExtendedTcpTable(IntPtr pTcpTable, ref int dwOutBufLen, bool sort, int ipVersion, TCP_TABLE_CLASS tblClass,int reserved);

VB Signature:

<DllImport("iphlpapi.dll", SetLastError:=True)> _
Public Shared Function GetExtendedTcpTable(ByVal pTcpTable As IntPtr, ByRef dwOutBufLen As Integer, ByVal sort As Boolean, ByVal ipVersion As  Integer, ByVal tblClass As TCP_TABLE_CLASS, ByVal reserved As Integer) As UInteger
End Function

User-Defined Types:

None.

Alternative Managed API:

Do you know one? Please contribute it!

When yu do not need the PID information look at: IPGlobalProperties.GetActiveTcpListeners Method from the System.Net.NetworkInformation namespace

(Msdn: http://msdn.microsoft.com/en-us/library/system.net.networkinformation.ipglobalproperties.getactivetcplisteners.aspx)

Notes:

Tips & Tricks:

Please add some!

Sample Code:

    [StructLayout(LayoutKind.Sequential)]
    public struct MIB_TCPROW_OWNER_PID
    {
        public uint state;
        public uint localAddr;
        public byte localPort1;
        public byte localPort2;
        public byte localPort3;
        public byte localPort4;
        public uint remoteAddr;
        public byte remotePort1;
        public byte remotePort2;
        public byte remotePort3;
        public byte remotePort4;
        public int owningPid;
    }
    [StructLayout(LayoutKind.Sequential)]
    public struct MIB_TCPTABLE_OWNER_PID
    {
        public uint dwNumEntries;
        MIB_TCPROW_OWNER_PID table;
    }

    enum TCP_TABLE_CLASS
    {
        TCP_TABLE_BASIC_LISTENER,
        TCP_TABLE_BASIC_CONNECTIONS,
        TCP_TABLE_BASIC_ALL,
        TCP_TABLE_OWNER_PID_LISTENER,
        TCP_TABLE_OWNER_PID_CONNECTIONS,
        TCP_TABLE_OWNER_PID_ALL,
        TCP_TABLE_OWNER_MODULE_LISTENER,
        TCP_TABLE_OWNER_MODULE_CONNECTIONS,
        TCP_TABLE_OWNER_MODULE_ALL
    }

    //public TcpRow[] GetAllTcpConnections()
    public MIB_TCPROW_OWNER_PID[] GetAllTcpConnections()
    {
    //  TcpRow is my own class to display returned rows in a nice manner.
    //    TcpRow[] tTable;
        MIB_TCPROW_OWNER_PID[] tTable;
        int AF_INET = 2;    // IP_v4
        int buffSize = 0;

        // how much memory do we need?
        uint ret = GetExtendedTcpTable(IntPtr.Zero, ref buffSize, true, AF_INET, TCP_TABLE_CLASS.TCP_TABLE_OWNER_PID_ALL,0);        
        IntPtr buffTable = Marshal.AllocHGlobal(buffSize);

        try
        {
        ret = GetExtendedTcpTable(buffTable, ref buffSize, true, AF_INET, TCP_TABLE_CLASS.TCP_TABLE_OWNER_PID_ALL, 0);
        if (ret != 0)
        {
            return null;
        }

        // get the number of entries in the table
        //MibTcpTable tab = (MibTcpTable)Marshal.PtrToStructure(buffTable, typeof(MibTcpTable));
        MIB_TCPTABLE_OWNER_PID tab = (MIB_TCPTABLE_OWNER_PID)Marshal.PtrToStructure(buffTable, typeof(MIB_TCPTABLE_OWNER_PID));
        //IntPtr rowPtr = (IntPtr)((long)buffTable + Marshal.SizeOf(tab.numberOfEntries) );
        IntPtr rowPtr = (IntPtr)((long)buffTable + Marshal.SizeOf(tab.dwNumEntries));
        // buffer we will be returning
        //tTable = new TcpRow[tab.numberOfEntries];
        tTable = new MIB_TCPROW_OWNER_PID[tab.dwNumEntries];

        //for (int i = 0; i < tab.numberOfEntries; i++)        
        for (int i = 0; i < tab.dwNumEntries; i++)
        {
            //MibTcpRow_Owner_Pid tcpRow = (MibTcpRow_Owner_Pid)Marshal.PtrToStructure(rowPtr, typeof(MibTcpRow_Owner_Pid));
            MIB_TCPROW_OWNER_PID tcpRow = (MIB_TCPROW_OWNER_PID)Marshal.PtrToStructure(rowPtr, typeof(MIB_TCPROW_OWNER_PID));
            //tTable[i] = new TcpRow(tcpRow);
            tTable[i] = tcpRow;
            rowPtr = (IntPtr)((long)rowPtr + Marshal.SizeOf(tcpRow));   // next entry
        }

        }
        finally
        {
        // Free the Memory
        Marshal.FreeHGlobal(buffTable);
        }

        return tTable;
    }

Changed by Al_Ex_OKT all work.

Please edit this page!

Do you have...

• helpful tips or sample code to share for using this API in managed code?
• corrections to the existing content?
• variations of the signature you want to share?
• additional languages you want to include?

Select "Edit This Page" on the right hand toolbar and edit it! Or add new pages containing supporting types needed for this API (structures, delegates, and more).