optimizer/Optimizer/UserFoldersHelper.cs

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;

namespace Optimizer
{
    internal static class KnownFolders
    {
        private static readonly Dictionary<KnownFolder, Guid> _guids = new Dictionary<KnownFolder, Guid>
        {
            [KnownFolder.Contacts] = new Guid("56784854-C6CB-462B-8169-88E350ACB882"),
            [KnownFolder.Downloads] = new Guid("374DE290-123F-4565-9164-39C4925E467B"),
            [KnownFolder.Favorites] = new Guid("1777F761-68AD-4D8A-87BD-30B759FA33DD"),
            [KnownFolder.Links] = new Guid("BFB9D5E0-C6A9-404C-B2B2-AE6DB6AF4968"),
            [KnownFolder.SavedGames] = new Guid("4C5C32FF-BB9D-43B0-B5B4-2D72E54EAAA4"),
            [KnownFolder.SavedSearches] = new Guid("7D1D3A04-DEBB-4115-95CF-2F29DA2920DA")
        };

        internal static string GetPath(KnownFolder knownFolder)
        {
            return SHGetKnownFolderPath(_guids[knownFolder], 0);
        }

        [DllImport("shell32",
            CharSet = CharSet.Unicode, ExactSpelling = true, PreserveSig = false)]
        private static extern string SHGetKnownFolderPath(
            [MarshalAs(UnmanagedType.LPStruct)] Guid rfid, uint dwFlags,
            uint hToken = 0);
    }
}