c# 4.0 - Drag-and-Drop multiple Attached File From Outlook to C# Window Form

Question

I Use following code for single file drag and drop.

 private void FormRegion2_DragEnter_1(object sender, DragEventArgs e)
    {
        if (e.Data.GetDataPresent(DataFormats.FileDrop))
        { e.Effect = DragDropEffects.Copy; }
        //    or this tells us if it is an Outlook attachment drop
        else if (e.Data.GetDataPresent("FileGroupDescriptor"))
        { e.Effect = DragDropEffects.Copy; }
        //    or none of the above
        else
        { e.Effect = DragDropEffects.None; }
    }

  private void FormRegion2_DragDrop_1(object sender, DragEventArgs e)
    {
        string[] fileNames = null;


        if (e.Data.GetDataPresent(DataFormats.FileDrop, false) == true)
        {
            fileNames = (string[])e.Data.GetData(DataFormats.FileDrop);                
            foreach (string fileName in fileNames)
            {
            }
        }
        else if (e.Data.GetDataPresent("FileGroupDescriptor"))
        {
           object s = e.Data.GetData("FileGroupDescriptor");

            Stream theStream = (Stream)e.Data.GetData("FileGroupDescriptor");
            byte[] fileGroupDescriptor = new byte[512];
            theStream.Read(fileGroupDescriptor, 0, 512);

            StringBuilder fileName = new StringBuilder("");

            for (int i = 76; fileGroupDescriptor[i] != 0; i++)
            { fileName.Append(Convert.ToChar(fileGroupDescriptor[i])); }

            string theFile = fileName.ToString();             
            String fileName1 = System.IO.Path.GetFileName(theFile);                

        }

    }

My problem is i am not able to get multiple file name. How it is possible to get multiple file name

Thx

Answer 1

I solve my problem Just add that code in any cs file.

using System;
using System.IO;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Runtime.InteropServices.ComTypes;
using System.Text;
using System.Reflection;
using System.Windows.Forms;

  namespace iwantedue.Windows.Forms
 {  

public class OutlookDataObject: System.Windows.Forms.IDataObject
{
    #region NativeMethods

    private class NativeMethods
    {
        [DllImport("kernel32.dll")]
        static extern IntPtr GlobalLock(IntPtr hMem);

        [DllImport("ole32.dll", PreserveSig = false)]
        public static extern ILockBytes CreateILockBytesOnHGlobal(IntPtr hGlobal, bool fDeleteOnRelease);

        [DllImport("OLE32.DLL", CharSet = CharSet.Auto, PreserveSig = false)]
        public static extern IntPtr GetHGlobalFromILockBytes(ILockBytes pLockBytes);

        [DllImport("OLE32.DLL", CharSet = CharSet.Unicode, PreserveSig = false)]
        public static extern IStorage StgCreateDocfileOnILockBytes(ILockBytes plkbyt, uint grfMode, uint reserved);

        [ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("0000000B-0000-0000-C000-000000000046")]
        public interface IStorage
        {
            [return: MarshalAs(UnmanagedType.Interface)]
            IStream CreateStream([In, MarshalAs(UnmanagedType.BStr)] string pwcsName, [In, MarshalAs(UnmanagedType.U4)] int grfMode, [In, MarshalAs(UnmanagedType.U4)] int reserved1, [In, MarshalAs(UnmanagedType.U4)] int reserved2);
            [return: MarshalAs(UnmanagedType.Interface)]
            IStream OpenStream([In, MarshalAs(UnmanagedType.BStr)] string pwcsName, IntPtr reserved1, [In, MarshalAs(UnmanagedType.U4)] int grfMode, [In, MarshalAs(UnmanagedType.U4)] int reserved2);
            [return: MarshalAs(UnmanagedType.Interface)]
            IStorage CreateStorage([In, MarshalAs(UnmanagedType.BStr)] string pwcsName, [In, MarshalAs(UnmanagedType.U4)] int grfMode, [In, MarshalAs(UnmanagedType.U4)] int reserved1, [In, MarshalAs(UnmanagedType.U4)] int reserved2);
            [return: MarshalAs(UnmanagedType.Interface)]
            IStorage OpenStorage([In, MarshalAs(UnmanagedType.BStr)] string pwcsName, IntPtr pstgPriority, [In, MarshalAs(UnmanagedType.U4)] int grfMode, IntPtr snbExclude, [In, MarshalAs(UnmanagedType.U4)] int reserved);
            void CopyTo(int ciidExclude, [In, MarshalAs(UnmanagedType.LPArray)] Guid[] pIIDExclude, IntPtr snbExclude, [In, MarshalAs(UnmanagedType.Interface)] IStorage stgDest);
            void MoveElementTo([In, MarshalAs(UnmanagedType.BStr)] string pwcsName, [In, MarshalAs(UnmanagedType.Interface)] IStorage stgDest, [In, MarshalAs(UnmanagedType.BStr)] string pwcsNewName, [In, MarshalAs(UnmanagedType.U4)] int grfFlags);
            void Commit(int grfCommitFlags);
            void Revert();
            void EnumElements([In, MarshalAs(UnmanagedType.U4)] int reserved1, IntPtr reserved2, [In, MarshalAs(UnmanagedType.U4)] int reserved3, [MarshalAs(UnmanagedType.Interface)] out object ppVal);
            void DestroyElement([In, MarshalAs(UnmanagedType.BStr)] string pwcsName);
            void RenameElement([In, MarshalAs(UnmanagedType.BStr)] string pwcsOldName, [In, MarshalAs(UnmanagedType.BStr)] string pwcsNewName);
            void SetElementTimes([In, MarshalAs(UnmanagedType.BStr)] string pwcsName, [In] System.Runtime.InteropServices.ComTypes.FILETIME pctime, [In] System.Runtime.InteropServices.ComTypes.FILETIME patime, [In] System.Runtime.InteropServices.ComTypes.FILETIME pmtime);
            void SetClass([In] ref Guid clsid);
            void SetStateBits(int grfStateBits, int grfMask);
            void Stat([Out]out System.Runtime.InteropServices.ComTypes.STATSTG pStatStg, int grfStatFlag);
        }

        [ComImport, Guid("0000000A-0000-0000-C000-000000000046"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        public interface ILockBytes
        {
            void ReadAt([In, MarshalAs(UnmanagedType.U8)] long ulOffset, [Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 1)] byte[] pv, [In, MarshalAs(UnmanagedType.U4)] int cb, [Out, MarshalAs(UnmanagedType.LPArray)] int[] pcbRead);
            void WriteAt([In, MarshalAs(UnmanagedType.U8)] long ulOffset, IntPtr pv, [In, MarshalAs(UnmanagedType.U4)] int cb, [Out, MarshalAs(UnmanagedType.LPArray)] int[] pcbWritten);
            void Flush();
            void SetSize([In, MarshalAs(UnmanagedType.U8)] long cb);
            void LockRegion([In, MarshalAs(UnmanagedType.U8)] long libOffset, [In, MarshalAs(UnmanagedType.U8)] long cb, [In, MarshalAs(UnmanagedType.U4)] int dwLockType);
            void UnlockRegion([In, MarshalAs(UnmanagedType.U8)] long libOffset, [In, MarshalAs(UnmanagedType.U8)] long cb, [In, MarshalAs(UnmanagedType.U4)] int dwLockType);
            void Stat([Out]out System.Runtime.InteropServices.ComTypes.STATSTG pstatstg, [In, MarshalAs(UnmanagedType.U4)] int grfStatFlag);
        }

        [StructLayout(LayoutKind.Sequential)]
        public sealed class POINTL
        {
            public int x;
            public int y;
        }

        [StructLayout(LayoutKind.Sequential)]
        public sealed class SIZEL
        {
            public int cx;
            public int cy;
        }

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
        public sealed class FILEGROUPDESCRIPTORA
        {
            public uint cItems;
            public FILEDESCRIPTORA[] fgd;
        }

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
        public sealed class FILEDESCRIPTORA
        {
            public uint dwFlags;
            public Guid clsid;
            public SIZEL sizel;
            public POINTL pointl;
            public uint dwFileAttributes;
            public System.Runtime.InteropServices.ComTypes.FILETIME ftCreationTime;
            public System.Runtime.InteropServices.ComTypes.FILETIME ftLastAccessTime;
            public System.Runtime.InteropServices.ComTypes.FILETIME ftLastWriteTime;
            public uint nFileSizeHigh;
            public uint nFileSizeLow;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
            public string cFileName;
        }

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        public sealed class FILEGROUPDESCRIPTORW
        {
            public uint cItems;
            public FILEDESCRIPTORW[] fgd;
        }

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        public sealed class FILEDESCRIPTORW
        {
            public uint dwFlags;
            public Guid clsid;
            public SIZEL sizel;
            public POINTL pointl;
            public uint dwFileAttributes;
            public System.Runtime.InteropServices.ComTypes.FILETIME ftCreationTime;
            public System.Runtime.InteropServices.ComTypes.FILETIME ftLastAccessTime;
            public System.Runtime.InteropServices.ComTypes.FILETIME ftLastWriteTime;
            public uint nFileSizeHigh;
            public uint nFileSizeLow;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
            public string cFileName;
        }
    }

    #endregion

    #region Property(s)

    /// <summary>
    /// Holds the <see cref="System.Windows.Forms.IDataObject"/> that this class is wrapping
    /// </summary>
    private System.Windows.Forms.IDataObject underlyingDataObject;



    private System.Runtime.InteropServices.ComTypes.IDataObject comUnderlyingDataObject;



    private System.Windows.Forms.IDataObject oleUnderlyingDataObject;
    private MethodInfo getDataFromHGLOBLALMethod;
    #endregion

    #region Constructor(s)

    public OutlookDataObject(System.Windows.Forms.IDataObject underlyingDataObject)
    {

        this.underlyingDataObject = underlyingDataObject;
        this.comUnderlyingDataObject = (System.Runtime.InteropServices.ComTypes.IDataObject)this.underlyingDataObject;

        FieldInfo innerDataField = this.underlyingDataObject.GetType().GetField("innerData", BindingFlags.NonPublic | BindingFlags.Instance);
        this.oleUnderlyingDataObject = (System.Windows.Forms.IDataObject)innerDataField.GetValue(this.underlyingDataObject);
        this.getDataFromHGLOBLALMethod = this.oleUnderlyingDataObject.GetType().GetMethod("GetDataFromHGLOBLAL", BindingFlags.NonPublic | BindingFlags.Instance);
    }

    #endregion

    #region IDataObject Members

    public object GetData(Type format)
    {
        return this.GetData(format.FullName);
    }


    public object GetData(string format)
    {
        return this.GetData(format, true);
    }

    public object GetData(string format, bool autoConvert)
    {
        switch(format)
        {
            case "FileGroupDescriptor":
                IntPtr fileGroupDescriptorAPointer = IntPtr.Zero;
                try
                {
                    //use the underlying IDataObject to get the FileGroupDescriptor as a MemoryStream
                    MemoryStream fileGroupDescriptorStream = (MemoryStream)this.underlyingDataObject.GetData("FileGroupDescriptor", autoConvert);
                    byte[] fileGroupDescriptorBytes = new byte[fileGroupDescriptorStream.Length];
                    fileGroupDescriptorStream.Read(fileGroupDescriptorBytes, 0, fileGroupDescriptorBytes.Length);
                    fileGroupDescriptorStream.Close();

                    //copy the file group descriptor into unmanaged memory 
                    fileGroupDescriptorAPointer = Marshal.AllocHGlobal(fileGroupDescriptorBytes.Length);
                    Marshal.Copy(fileGroupDescriptorBytes, 0, fileGroupDescriptorAPointer, fileGroupDescriptorBytes.Length);

                    //marshal the unmanaged memory to to FILEGROUPDESCRIPTORA struct
                    object fileGroupDescriptorObject = Marshal.PtrToStructure(fileGroupDescriptorAPointer, typeof(NativeMethods.FILEGROUPDESCRIPTORA));
                    NativeMethods.FILEGROUPDESCRIPTORA fileGroupDescriptor = (NativeMethods.FILEGROUPDESCRIPTORA)fileGroupDescriptorObject;

                    //create a new array to store file names in of the number of items in the file group descriptor
                    string[] fileNames = new string[fileGroupDescriptor.cItems];

                    //get the pointer to the first file descriptor
                    IntPtr fileDescriptorPointer = (IntPtr)((int)fileGroupDescriptorAPointer + Marshal.SizeOf(fileGroupDescriptor.cItems));

                    //loop for the number of files acording to the file group descriptor
                    for(int fileDescriptorIndex = 0;fileDescriptorIndex < fileGroupDescriptor.cItems;fileDescriptorIndex++)
                    {

                        //marshal the pointer top the file descriptor as a FILEDESCRIPTORA struct and get the file name
                        NativeMethods.FILEDESCRIPTORA fileDescriptor = (NativeMethods.FILEDESCRIPTORA)Marshal.PtrToStructure(fileDescriptorPointer, typeof(NativeMethods.FILEDESCRIPTORA));
                        fileNames[fileDescriptorIndex] = fileDescriptor.cFileName;

                        //move the file descriptor pointer to the next file descriptor
                        fileDescriptorPointer = (IntPtr)((int)fileDescriptorPointer + Marshal.SizeOf(fileDescriptor));
                    }

                    //return the array of filenames
                    return fileNames;
                }
                finally
                {
                    //free unmanaged memory pointer
                    Marshal.FreeHGlobal(fileGroupDescriptorAPointer);
                }

            case "FileGroupDescriptorW":
                //override the default handlin