GeekDesk/Util/DefaultIcons.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace GeekDesk.Util
{
    public static class DefaultIcons
    {
        private static Icon folderIcon;

        public static Icon FolderLarge => folderIcon ?? (folderIcon = GetStockIcon(SHGSI_ICON, SHGSI_LARGEICON));

        public static Icon GetStockIcon(uint type, uint size)
        {
            var info = new SHSTOCKICONINFO();
            info.cbSize = (uint)Marshal.SizeOf(info);

            SHGetStockIconInfo(type, SHGSI_ICON | size, ref info);

            var icon = (Icon)Icon.FromHandle(info.hIcon).Clone(); // Get a copy that doesn't use the original handle
            DestroyIcon(info.hIcon); // Clean up native icon to prevent resource leak

            return icon;
        }

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        public struct SHSTOCKICONINFO
        {
            public uint cbSize;
            public IntPtr hIcon;
            public int iSysIconIndex;
            public int iIcon;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
            public string szPath;
        }

        [DllImport("shell32.dll")]
        public static extern int SHGetStockIconInfo(uint siid, uint uFlags, ref SHSTOCKICONINFO psii);

        [DllImport("user32.dll")]
        public static extern bool DestroyIcon(IntPtr handle);

        public static uint SHSIID_FOLDER = 0x3;
        public static uint SHGSI_ICON = 0x100;
        public static uint SHGSI_LARGEICON = 0x0;
        public static uint SHGSI_SMALLICON = 0x1;
    }
}