C#: How to open Windows Explorer windows with a number of files selected

Question

In the Library of Windows Media Player you can select one or more music files. You can then right-click and in their context menu choose Open File Location. This will open up one windows explorer window for each directory that the files are in, and the files will be selected for you.

So let's say we have a bunch of mp3 files in our library where three of them are these:

• Z:\Music\Thursday Blues\01. I wish it was friday.mp3
• Z:\Music\Counting Sheep\01. Sheep #1.mp3
• Z:\Music\Counting Sheep\02. Sheep #2.mp3

If we select those three (in a view where all of them are visible) and do Open File Location then two explorer windows will pop up. One will be the Z:\Music\Thursday Blues folder with 01. I wish it was friday.mp3 selected, and the other one will be the *Z:\Music\Counting Sheep** folder with both 01. Sheep #1.mp3 and 02. Sheep #2.mp3 selected.

How can I do this myself in C#? We have an application which is going to export data to various formats, for example CSV and Excel, and I would like to open up explorer windows with these files selected when they are created and ready to be viewed. Currently I just do Process.Start(path), and this works but I would love to be able to highlight those particular files as well. Would make the files that were just created much more obvious.

---

Windows Media Player does it so well... I want to do it too =/ Are there any Microsoft employees here that could figure out how it can be done? (A)

Answer 1

Searching for an answer after a coworker had the issue i found none so i wrote a small class to do this. The code is on Gist and i will paste the curent version at the end of this post.

With your sample files, the syntax will be :

ShowSelectedInExplorer.FilesOrFolders(
    @"Z:\Music\Thursday Blues\01. I wish it was friday.mp3",
    @"Z:\Music\Counting Sheep\01. Sheep #1.mp3",
    @"Z:\Music\Counting Sheep\02. Sheep #2.mp3"
    );

There are some limitations to my code compared to the low level API, mainly :

• Selecting on the desktop is not implemented
• The parent directory must be a directory or a drive, so you can't select multiple drives in the My Computer folder for example.

Anyway, here is the ShowSelectedInExplorer class source code :

namespace SHOpenFolderAndSelectItems
{
    using System;
    using System.Collections.Generic;
    using System.IO;
    using System.Linq;
    using System.Runtime.CompilerServices;
    using System.Runtime.InteropServices;
    using System.Runtime.InteropServices.ComTypes;

    static class ShowSelectedInExplorer
    {
        [Flags]
        enum SHCONT : ushort
        {
            SHCONTF_CHECKING_FOR_CHILDREN = 0x0010,
            SHCONTF_FOLDERS = 0x0020,
            SHCONTF_NONFOLDERS = 0x0040,
            SHCONTF_INCLUDEHIDDEN = 0x0080,
            SHCONTF_INIT_ON_FIRST_NEXT = 0x0100,
            SHCONTF_NETPRINTERSRCH = 0x0200,
            SHCONTF_SHAREABLE = 0x0400,
            SHCONTF_STORAGE = 0x0800,
            SHCONTF_NAVIGATION_ENUM = 0x1000,
            SHCONTF_FASTITEMS = 0x2000,
            SHCONTF_FLATLIST = 0x4000,
            SHCONTF_ENABLE_ASYNC = 0x8000
        }

        [ComImport,
        Guid("000214E6-0000-0000-C000-000000000046"),
        InterfaceType(ComInterfaceType.InterfaceIsIUnknown),
        ComConversionLoss]
        interface IShellFolder
        {
            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            void ParseDisplayName(IntPtr hwnd, [In, MarshalAs(UnmanagedType.Interface)] IBindCtx pbc, [In, MarshalAs(UnmanagedType.LPWStr)] string pszDisplayName, [Out] out uint pchEaten, [Out] out IntPtr ppidl, [In, Out] ref uint pdwAttributes);
            [PreserveSig]
            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            int EnumObjects([In] IntPtr hwnd, [In] SHCONT grfFlags, [MarshalAs(UnmanagedType.Interface)] out IEnumIDList ppenumIDList);

            [PreserveSig]
            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            int BindToObject([In] IntPtr pidl, [In, MarshalAs(UnmanagedType.Interface)] IBindCtx pbc, [In] ref Guid riid, [Out, MarshalAs(UnmanagedType.Interface)] out IShellFolder ppv);

            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            void BindToStorage([In] ref IntPtr pidl, [In, MarshalAs(UnmanagedType.Interface)] IBindCtx pbc, [In] ref Guid riid, out IntPtr ppv);

            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            void CompareIDs([In] IntPtr lParam, [In] ref IntPtr pidl1, [In] ref IntPtr pidl2);

            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            void CreateViewObject([In] IntPtr hwndOwner, [In] ref Guid riid, out IntPtr ppv);

            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            void GetAttributesOf([In] uint cidl, [In] IntPtr apidl, [In, Out] ref uint rgfInOut);


            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            void GetUIObjectOf([In] IntPtr hwndOwner, [In] uint cidl, [In] IntPtr apidl, [In] ref Guid riid, [In, Out] ref uint rgfReserved, out IntPtr ppv);

            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            void GetDisplayNameOf([In] ref IntPtr pidl, [In] uint uFlags, out IntPtr pName);

            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            void SetNameOf([In] IntPtr hwnd, [In] ref IntPtr pidl, [In, MarshalAs(UnmanagedType.LPWStr)] string pszName, [In] uint uFlags, [Out] IntPtr ppidlOut);
        }

        [ComImport,
        Guid("000214F2-0000-0000-C000-000000000046"),
        InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        interface IEnumIDList
        {
            [PreserveSig]
            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            int Next(uint celt, IntPtr rgelt, out uint pceltFetched);

            [PreserveSig]
            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            int Skip([In] uint celt);

            [PreserveSig]
            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            int Reset();

            [PreserveSig]
            [MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime)]
            int Clone([MarshalAs(UnmanagedType.Interface)] out IEnumIDList ppenum);
        }

        static class NativeMethods
        {
            [DllImport("shell32.dll", EntryPoint = "SHGetDesktopFolder", CharSet = CharSet.Unicode,
                SetLastError = true)]
            static extern int SHGetDesktopFolder_([MarshalAs(UnmanagedType.Interface)] out IShellFolder ppshf);

            public static IShellFolder SHGetDesktopFolder()
            {
                IShellFolder result;
                Marshal.ThrowExceptionForHR(SHGetDesktopFolder_(out result));
                return result;
            }

            [DllImport("shell32.dll", EntryPoint = "SHOpenFolderAndSelectItems")]
            static extern int SHOpenFolderAndSelectItems_(
                [In] IntPtr pidlFolder, uint cidl, [In, Optional, MarshalAs(UnmanagedType.LPArray)] IntPtr[] apidl,
                int dwFlags);

            public static void SHOpenFolderAndSelectItems(IntPtr pidlFolder, IntPtr[] apidl, int dwFlags)
            {
                var cidl = (apidl != null) ? (uint)apidl.Length : 0U;
                var result = SHOpenFolderAndSelectItems_(pidlFolder, cidl, apidl, dwFlags);
                Marshal.ThrowExceptionForHR(result);
            }

            [DllImport("shell32.dll")]
            public static extern void ILFree([In] IntPtr pidl);
        }

        static IntPtr GetShellFolderChildrenRelativePIDL(IShellFolder parentFolder, string displayName)
        {
            uint pchEaten;
            uint pdwAttributes = 0;
            IntPtr ppidl;
            parentFolder.ParseDisplayName(IntPtr.Zero, null, displayName, out pchEaten, out ppidl, ref pdwAttributes);

            return ppidl;
        }

        static IntPtr PathToAbsolutePIDL(string path)
        {
            var desktopFolder = NativeMethods.SHGetDesktopFolder();
            return GetShellFolderChildrenRelativePIDL(desktopFolder, path);
        }

        static Guid IID_IShellFolder = typeof(IShellFolder).GUID;

        static IShellFolder PIDLToShellFolder(IShellFolder parent, IntPtr pidl)
        {
            IShellFolder folder;
            var result = parent.BindToObject(pidl, null, ref IID_IShellFolder, out folder);
            Marshal.ThrowExceptionForHR((int)result);
            return folder;
        }

        static IShellFolder PIDLToShellFolder(IntPtr pidl)
        {
            return PIDLToShellFolder(NativeMethods.SHGetDesktopFolder(), pidl);
        }

        static void SHOpenFolderAndSelectItems(IntPtr pidlFolder, IntPtr[] apidl, bool edit)
        {
            NativeMethods.SHOpenFolderAndSelectItems(pidlFolder, apidl, edit ? 1 : 0);
        }

        public static void FileOrFolder(string path, bool edit = false)
        {
            if (path == null) throw new ArgumentNullException("path");

            var pidl = PathToAbsolutePIDL(path);
            try
            {
                SHOpenFolderAndSelectItems(pidl, null, edit);
            }
            finally
            {
                NativeMethods.ILFree(pidl);
            }
        }

        static IEnumerable<FileSystemInfo> PathToFileSystemInfo(IEnumerable<string> paths)
        {
            foreach (var path in paths)
            {
                var fixedPath = path;
                if (fixedPath.EndsWith(Path.DirectorySeparatorChar.ToString())
                    || fixedPath.EndsWith(Path.AltDirectorySeparatorChar.ToString()))
                {
                    fixedPath = fixedPath.Remove(fixedPath.Length - 1);
                }

                if (Directory.Exists(fixedPath))
                {
                    yield return new DirectoryInfo(fixedPath);
                }
                else if (File.Exists(fixedPath))
                {
                    yield return new FileInfo(fixedPath);
                }
                else
                {
                    throw new FileNotFoundException
                        (string.Format("The specified file or folder doesn't exists : {0}", fixedPath),
                        fixedPath);
                }
            }
        }

        public static void FilesOrFolders(string parentDirectory, ICollection<string> filenames)
        {
            if (filenames == null) throw new ArgumentNullException("filenames");
            if (filenames.Count == 0) return;

            var parentPidl = PathToAbsolutePIDL(parentDirectory);
            try
            {
                var parent = PIDLToShellFolder(parentPidl);
                var filesPidl = filenames
                    .Select(filename => GetShellFolderChildrenRelativePIDL(parent, filename))
                    .ToArray();

                try
                {
                    SHOpenFolderAndSelectItems(parentPidl, filesPidl, false);
                }
                finally
                {
                    foreach (var pidl in filesPidl)
                    {
                        NativeMethods.ILFree(pidl);
                    }
                }
            }
            finally
            {
                NativeMethods.ILFree(parentPidl);
            }
        }

        public static void FilesOrFolders(params string[] paths)
        {
            FilesOrFolders((IEnumerable<string>)paths);
        }

        public static void FilesOrFolders(IEnumerable<string> paths)
        {
            if (paths == null) throw new ArgumentNullException("paths");

            FilesOrFolders(PathToFileSystemInfo(paths));
        }

        public static void FilesOrFolders(IEnumerable<FileSystemInfo> paths)
        {
            if (paths == null) throw new ArgumentNullException("paths");
            var pathsArray = paths.ToArray();
            if (pathsArray.Count() == 0) return;

            var explorerWindows = pathsArray.GroupBy(p => Path.GetDirectoryName(p.FullName));

            foreach (var explorerWindowPaths in explorerWindows)
            {
                var parentDirectory = Path.GetDirectoryName(explorerWindowPaths.First().FullName);
                FilesOrFolders(parentDirectory, explorerWindowPaths.Select(fsi => fsi.Name).ToList());
            }
        }
    }

    class Program
    {
        static void Main()
        {

            var test = 3;
            switch (test)
            {
                case 0:
                    var mydocs = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
                    ShowSelectedInExplorer.FileOrFolder(Path.Combine(mydocs, "Visual Studio 2010"), edit: true);

                    break;

                case 1:
                    ShowSelectedInExplorer.FileOrFolder(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile));
                    break;

                case 2:
                    ShowSelectedInExplorer.FilesOrFolders(@"C:\Windows\", new[] { "Microsoft.NET", "System32", "Setup" });
                    break;

                case 3:
                    ShowSelectedInExplorer.FilesOrFolders(@"C:\Windows\Microsoft.NET\", @"C:\Windows\System32", @"C:\Windows\Setup", @"C:\Program Files");
                    break;
            }
        }
    }
}

Answer 2

Disclaimer: I think VirtualBlackFox's answer is better than mine although it has less votes at present, so scroll down and read that one first :)

Easy method (might not work on all platforms):

Process.Start(String, String)

First argument is the application, second argument is the command line parameters of the application..

So for example:

Process.Start("explorer.exe",
"/select,Z:\Music\Thursday Blues\01. I wish it was friday.mp3")

Process.Start("explorer.exe",
"/select,Z:\Music\Counting Sheep\01. Sheep #1.mp3 /select,Z:\Music\Counting Sheep\02. Sheep #2.mp3")

(I think you might need escaped quotes around the file paths if they have spaces).

more info: http://msdn.microsoft.com/en-us/library/h6ak8zt5.aspx

(compiled from several answers to this question)

---

Harder method, but more likely to work, taken from this answer to another question:

Use the shell function SHOpenFolderAndSelectItems

Here is some sample code showing how to use the function in C/C++, without error checking:

//Directory to open
ITEMIDLIST *dir = ILCreateFromPath(_T("C:\\"));

//Items in directory to select
ITEMIDLIST *item1 = ILCreateFromPath(_T("C:\\Program Files\\"));
ITEMIDLIST *item2 = ILCreateFromPath(_T("C:\\Windows\\"));
const ITEMIDLIST* selection[] = {item1,item2};
UINT count = sizeof(selection) / sizeof(ITEMIDLIST);

//Perform selection
SHOpenFolderAndSelectItems(dir, count, selection, 0);

//Free resources
ILFree(dir);
ILFree(item1);
ILFree(item2);

Answer 3

Try starting this:

explorer.exe /select,Z:\Music\Thursday Blues\01. I wish it was friday.mp3