The Initialize method is called when File Explorer is initializing a context menu extension, a property sheet extension, or a non-default drag-and-drop extension.

C# Definition:

[ComImport(),InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[GuidAttribute("000214e8-0000-0000-c000-000000000046")]
public interface IShellExtInit
{
    [PreserveSig()]
    int Initialize (IntPtr pidlFolder, IntPtr lpdobj, uint /*HKEY*/ hKeyProgID);
}

VB Definition:

<ComImport(), InterfaceType(ComInterfaceType.InterfaceIsIUnknown),
  GuidAttribute("000214e8-0000-0000-c000-000000000046")> _
Public Interface IShellExtInit
    <PreserveSig()> _
    Function Initialize(ByVal pidlFolder As IntPtr, ByVal lpdobj As IntPtr, ByVal hKeyProgID As IntPtr) As Integer
End Interface 'IShellExtInit

User-Defined Types:

None.

Notes:

None.