private static Icon LoadIconFromResource(UIntPtr lpIconName)
{
HandleRef hmodule = new HandleRef(null, GetModuleHandle(null));
uint totalsize;
RESOURCE_ICONDIRENTRY[] entries;
SafeResourceBuffer[] entrybuffers;
RESOURCE_ICONDIR dir;
using (SafeResourceBuffer buffer = GetResourceBuffer(hmodule, lpIconName, MAKEINTRESOURCE(RT_GROUP_ICON)))
{
dir = buffer.Read <RESOURCE_ICONDIR>(0);
if (dir.idReserved != 0 || dir.idType != IMAGE_ICON || dir.idCount == 0)
{
throw new InvalidDataException("There is no icon directory in resource data.");
}
entries = new RESOURCE_ICONDIRENTRY[dir.idCount];
entrybuffers = new SafeResourceBuffer[dir.idCount];
uint entrysize = (uint)Marshal.SizeOf(typeof(RESOURCE_ICONDIRENTRY));
ulong offset = (uint)Marshal.SizeOf(typeof(RESOURCE_ICONDIR)) - entrysize;
totalsize = (uint)(Marshal.SizeOf(typeof(ICONDIR)) + (Marshal.SizeOf(typeof(ICONDIRENTRY)) * (dir.idCount - 1)));
entries[0] = dir.idEntries;
for (int i = 0; i < dir.idCount; i++, offset += entrysize)
{
if (i > 0)
{
entries[i] = buffer.Read <RESOURCE_ICONDIRENTRY>(offset);
}
uint iconsize = entries[i].dwBytesInRes;
SafeResourceBuffer entrybuffer = GetResourceBuffer(hmodule, MAKEINTRESOURCE(entries[i].nID), MAKEINTRESOURCE(RT_ICON));
if (iconsize != entrybuffer.ByteLength)
{
throw new InvalidDataException("Reported resource size is not equal to the icon size.");
}
entrybuffers[i] = entrybuffer;
totalsize += iconsize;
}
}
using (SafeLocalAllocHandle iconbuffer = SafeLocalAlloc(LMEM_ZEROINIT | LMEM_FIXED, totalsize))
{
using (UnmanagedMemoryStream outstream = iconbuffer.ToStream(FileAccess.ReadWrite))
{
ICONDIR icondir = new ICONDIR(dir);
iconbuffer.Write(0, icondir);
uint iconoffset = icondir.idEntries.dwImageOffset;
outstream.Position = iconoffset;
uint entrysize = (uint)Marshal.SizeOf(typeof(ICONDIRENTRY));
ulong offset = (uint)Marshal.SizeOf(typeof(ICONDIR));
ICONDIRENTRY entry = icondir.idEntries;
for (int i = 0; i < dir.idCount; i++, offset += entrysize)
{
if (i > 0)
{
entry = new ICONDIRENTRY(entries[i], iconoffset);
iconbuffer.Write(offset, entry);
}
using (UnmanagedMemoryStream instream = entrybuffers[i].ToStream())
{
instream.CopyTo(outstream);
}
if (outstream.Position != (iconoffset + entry.dwBytesInRes))
{
throw new InvalidOperationException();
}
iconoffset += entry.dwBytesInRes;
}
outstream.Position = 0;
return(new Icon(outstream));
}
}
}