C# Definition:

struct PROPSPEC {
   public PROPSPECKIND ulKind;    // PRSPEC_LPWSTR or PRSPEC_PROPID
   public IntPtr data;
}

VB Definition:

#Region "PROPSPEC Structure Definition"

  '/// <summary>
  '/// The PROPSPEC structure is used by many of the methods of
  '/// IPropertyStorage to specify a property either by its property
  '/// identifier (ID) or the associated string name.
  '/// </summary>
  <StructLayout(LayoutKind.Sequential)> _
  Public Structure PROPSPEC
    '/// <summary>
    '/// Indicates whether the propid or lpwstr member used.
    '/// </summary>
    Public ulKind As PROPSPECKIND

    '/// <summary>
    '/// Specifies the value of the property ID. Use either this value or the following lpwstr, not both.
    '/// </summary>
    Public propid As UInt32

    '/// <summary>
    '/// Specifies the string name of the property as a null-terminated Unicode string.
    '/// </summary>
    Public lpwstr As IntPtr
  End Structure

#End Region

User-Defined Field Types:

PROPSPECKIND

Notes:

None.