[DllImport("shlwapi.dll", EntryPoint = "PathIsDirectoryW",  SetLastError = True, CharSet= CharSet.Unicode)]

static extern bool PathIsDirectory([MarshalAs(UnmanagedType.LPTStr)]string pszPath);

<DllImport("shlwapi.dll", EntryPoint:="PathIsDirectoryW",  SetLastError:=True, CharSet:=CharSet.Unicode)> _

Public Function PathIsDirectory(<MarshalAs(UnmanagedType.LPTStr)>pszPath As String) As <MarshalAs(UnmanagedType.Bool)> Boolean

Public Declare Function PathIsDirectory Lib "shlwapi" Alias "PathIsDirectoryA" _