/// <summary>
/// Parses the HDROP format and returns a list of strings using
/// the DragQueryFile function.
/// </summary>
private string[]? ReadFileListFromHandle(IntPtr hdrop)
{
uint count = Shell32.DragQueryFileW(hdrop, 0xFFFFFFFF, null);
if (count == 0)
{
return(null);
}
var sb = new StringBuilder(Kernel32.MAX_PATH);
var files = new string[count];
for (uint i = 0; i < count; i++)
{
uint charlen = Shell32.DragQueryFileW(hdrop, i, sb);
if (charlen == 0)
{
continue;
}
string s = sb.ToString(0, (int)charlen);
files[i] = s;
}
return(files);
}
public void OnDropFiles(ref DropFilesPacket packet)
{
IntPtr hDrop = packet.HDrop;
try
{
uint count = Shell32.DragQueryFileW(hDrop, 0xFFFFFFFF, IntPtr.Zero, 0);
var paths = new string[(int)count];
for (uint i = 0; i < count; i++)
{
uint size = Shell32.DragQueryFileW(hDrop, i, IntPtr.Zero, 0);
char[] chars = ArrayPool <char> .Shared.Rent((int)(size + 1));
try
{
GCHandle handle = GCHandle.Alloc(chars, GCHandleType.Pinned);
try
{
Shell32.DragQueryFileW(hDrop, i, handle.AddrOfPinnedObject(), size + 1);
paths[i] = new string(chars.AsSpan(0, (int)size));
}
finally
{
if (handle.IsAllocated)
{
handle.Free();
}
}
}
finally
{
ArrayPool <char> .Shared.Return(chars);
}
}
OnFilesDropped(paths);
}
finally
{
Shell32.DragFinish(hDrop);
}
}