Reading compound documents in c#

Question

I'm starting a project which requires reading outlook msg files in c#. I have the specs for compound documents but am having trouble reading them in c#. Any pointers would be greatly appreciated.

Thanks.

Answer 1

Here is my shot. This is an initial translation of this article.

namespace cs_console_app
{
    using System;
    using System.Runtime.InteropServices;
    using System.Runtime.InteropServices.ComTypes;

    [ComImport]
    [Guid("0000000d-0000-0000-C000-000000000046")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    public interface IEnumSTATSTG
    {
        // The user needs to allocate an STATSTG array whose size is celt.
        [PreserveSig]
        uint Next(
            uint celt,
            [MarshalAs(UnmanagedType.LPArray), Out]
            System.Runtime.InteropServices.ComTypes.STATSTG[] rgelt,
            out uint pceltFetched
        );

        void Skip(uint celt);

        void Reset();

        [return: MarshalAs(UnmanagedType.Interface)]
        IEnumSTATSTG Clone();
    }

    [ComImport]
    [Guid("0000000b-0000-0000-C000-000000000046")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    interface IStorage
    {
        void CreateStream(
            /* [string][in] */ string pwcsName,
            /* [in] */ uint grfMode,
            /* [in] */ uint reserved1,
            /* [in] */ uint reserved2,
            /* [out] */ out IStream ppstm);

        void OpenStream(
            /* [string][in] */ string pwcsName,
            /* [unique][in] */ IntPtr reserved1,
            /* [in] */ uint grfMode,
            /* [in] */ uint reserved2,
            /* [out] */ out IStream ppstm);

        void CreateStorage(
            /* [string][in] */ string pwcsName,
            /* [in] */ uint grfMode,
            /* [in] */ uint reserved1,
            /* [in] */ uint reserved2,
            /* [out] */ out IStorage ppstg);

        void OpenStorage(
            /* [string][unique][in] */ string pwcsName,
            /* [unique][in] */ IStorage pstgPriority,
            /* [in] */ uint grfMode,
            /* [unique][in] */ IntPtr snbExclude,
            /* [in] */ uint reserved,
            /* [out] */ out IStorage ppstg);

        void CopyTo(
            /* [in] */ uint ciidExclude,
            /* [size_is][unique][in] */ Guid rgiidExclude, // should this be an array?
            /* [unique][in] */ IntPtr snbExclude,
            /* [unique][in] */ IStorage pstgDest);

        void MoveElementTo(
            /* [string][in] */ string pwcsName,
            /* [unique][in] */ IStorage pstgDest,
            /* [string][in] */ string pwcsNewName,
            /* [in] */ uint grfFlags);

        void Commit(
            /* [in] */ uint grfCommitFlags);

        void Revert();

        void EnumElements(
            /* [in] */ uint reserved1,
            /* [size_is][unique][in] */ IntPtr reserved2,
            /* [in] */ uint reserved3,
            /* [out] */ out IEnumSTATSTG ppenum);

        void DestroyElement(
            /* [string][in] */ string pwcsName);

        void RenameElement(
            /* [string][in] */ string pwcsOldName,
            /* [string][in] */ string pwcsNewName);

        void SetElementTimes(
            /* [string][unique][in] */ string pwcsName,
            /* [unique][in] */ System.Runtime.InteropServices.ComTypes.FILETIME pctime,
            /* [unique][in] */ System.Runtime.InteropServices.ComTypes.FILETIME patime,
            /* [unique][in] */ System.Runtime.InteropServices.ComTypes.FILETIME pmtime);

        void SetClass(
            /* [in] */ Guid clsid);

        void SetStateBits(
            /* [in] */ uint grfStateBits,
            /* [in] */ uint grfMask);

        void Stat(
            /* [out] */ out System.Runtime.InteropServices.ComTypes.STATSTG pstatstg,
            /* [in] */ uint grfStatFlag);

    }

    [Flags]
    public enum STGM : int
    {
        DIRECT = 0x00000000,
        TRANSACTED = 0x00010000,
        SIMPLE = 0x08000000,
        READ = 0x00000000,
        WRITE = 0x00000001,
        READWRITE = 0x00000002,
        SHARE_DENY_NONE = 0x00000040,
        SHARE_DENY_READ = 0x00000030,
        SHARE_DENY_WRITE = 0x00000020,
        SHARE_EXCLUSIVE = 0x00000010,
        PRIORITY = 0x00040000,
        DELETEONRELEASE = 0x04000000,
        NOSCRATCH = 0x00100000,
        CREATE = 0x00001000,
        CONVERT = 0x00020000,
        FAILIFTHERE = 0x00000000,
        NOSNAPSHOT = 0x00200000,
        DIRECT_SWMR = 0x00400000,
    }

    public enum STATFLAG : uint
    {
        STATFLAG_DEFAULT = 0,
        STATFLAG_NONAME = 1,
        STATFLAG_NOOPEN = 2
    }

    public enum STGTY : int
    {
        STGTY_STORAGE = 1,
        STGTY_STREAM = 2,
        STGTY_LOCKBYTES = 3,
        STGTY_PROPERTY = 4
    }

    class Program
    {
        [DllImport("ole32.dll")]
        private static extern int StgIsStorageFile(
            [MarshalAs(UnmanagedType.LPWStr)] string pwcsName);

        [DllImport("ole32.dll")]
        static extern int StgOpenStorage(
            [MarshalAs(UnmanagedType.LPWStr)] string pwcsName,
            IStorage pstgPriority,
            STGM grfMode,
            IntPtr snbExclude,
            uint reserved,
            out IStorage ppstgOpen);

        static void Main(string[] args)
        {
            string filename = @"f:\temp\treta2.msg";
            if (StgIsStorageFile(filename) == 0)
            {
                IStorage storage = null;
                if (StgOpenStorage(
                    filename,
                    null,
                    STGM.DIRECT | STGM.READ | STGM.SHARE_EXCLUSIVE,
                    IntPtr.Zero,
                    0,
                    out storage) == 0)
                {
                    System.Runtime.InteropServices.ComTypes.STATSTG statstg;
                    storage.Stat(out statstg, (uint) STATFLAG.STATFLAG_DEFAULT);

                    IEnumSTATSTG pIEnumStatStg = null;
                    storage.EnumElements(0, IntPtr.Zero, 0, out pIEnumStatStg);

                    System.Runtime.InteropServices.ComTypes.STATSTG[] regelt = { statstg };
                    uint fetched = 0;
                    uint res = pIEnumStatStg.Next(1, regelt, out fetched);

                    if (res == 0)
                    {
                        while (res != 1)
                        {
                            string strNode = statstg.pwcsName;
                            bool bNodeFound = false;

                            Console.WriteLine(strNode);

                            if (strNode == "__substg1.0_0E04001E"
                                || strNode == "__substg1.0_0E1D001E"
                                || strNode == "__substg1.0_1000001E"
                                || strNode == "__substg1.0_1013001E")
                            {
                                bNodeFound = true;
                            }

                            if (bNodeFound)
                            {
                                switch (statstg.type)
                                {
                                    case (int) STGTY.STGTY_STORAGE:
                                        {
                                            IStorage pIChildStorage;
                                            storage.OpenStorage(statstg.pwcsName,
                                               null,
                                               (uint) (STGM.READ | STGM.SHARE_EXCLUSIVE),
                                               IntPtr.Zero,
                                               0,
                                               out pIChildStorage);
                                        }
                                        break;
                                    case (int) STGTY.STGTY_STREAM:
                                        {
                                            IStream pIStream;
                                            storage.OpenStream(statstg.pwcsName,
                                               IntPtr.Zero,
                                               (uint)(STGM.READ | STGM.SHARE_EXCLUSIVE),
                                               0,
                                               out pIStream);

                                            byte[] data = new byte[255];

                                            pIStream.Read(data, 255, IntPtr.Zero);
                                        }
                                        break;
                                }
                            }

                            if ((res = pIEnumStatStg.Next(1, regelt, out fetched)) != 1)
                            {
                                statstg = regelt[0];
                            }
                        }
                    }
                }
            }

            Console.ReadLine();
        }
    }
}

Answer 2

Outlook Interop. While I have never used the outlook interop, you SHOULD be able to open the email messages with it.

MailItem Interface should be the interface that you need to access it.

Also, make sure that you release the com references after you are done with them