IFolderView.SelectAndPositionItems -> MarshalDirectiveException

Describe the bug

Vanara.PInvoke.Shell32.IFolderView (SelectAndPositionItems) Vanara.PInvoke.Shell32.IFolderView2 (SelectAndPositionItems)

System.Runtime.InteropServices.MarshalDirectiveException : ‘Cannot marshal ‘parameter 2’: Invalid managed/unmanaged type combination (Arrays of SafeHandles are not supported).’

What code is involved

...
PIDL[] pIDLs = { pidlsub };
Point[] points = { pt };

FolderView.SelectAndPositionItems(1, pIDLs, points, SVSIF.SVSI_POSITIONITEM);

Expected behavior No MarshalDirectiveException

Note pidlsub is valid, and work well with other PIDL related function. He is from IEnumIdList.Next

[dahall]

Thanks for testing my committed code. Glad it works for you. On you second post, I’m not sure what you are freeing with Marshal.FreeCoTaskMem(pidlSub); Using the implicit conversion from IntPtr to PIDL on the second line, you are telling PIDL to own the pointer and the allocated memory behind it. Calling Dispose on it frees all the memory allocated by the call to IStream_ReadPidl. Below is how I would have written the loop:

while (IStream_ReadPidl(stream, out IntPtr ppidlOut).Succeeded)
{
   using (PIDL pIDL = ppidlOut)
   {
      Point pt;
      byte[] ptByte = new byte[155];
      stream.Read(ptByte, ptByte.Length, IntPtr.Zero);

      BinaryFormatter bf = new BinaryFormatter();
      using (MemoryStream ms = new MemoryStream(ptByte))
      {
         object obj = (Point)bf.Deserialize(ms);
         ms.Position = 0;
         pt = (Point)obj;
      }

      ((NativeMethods.IFolderView)FolderView1).SelectAndPositionItems(1, new[] { ppidlOut }, new[] { pt }, SVSIF.SVSI_POSITIONITEM);
   }
}

[Sherulez]

Using the implicit conversion from IntPtr to PIDL on the second line, you are telling PIDL to own the pointer and the allocated memory behind it.

That’s what I thought but I was not sure, thank you for clarifying things.

using (PIDL pIDL = ppidlOut)

Ho I see, you are using using, this way pIDL will Dipose() itself.

Thank you for the code cleanup 😃