The PropertyItem.Id property in the .NET Framework 1.0 can be identified by the C++ property tag constants (810111)

INTRODUCTION

When you use the PropertyItem class to encapsulate a metadata property to be included in an image file, the PropertyItem.Id property is of type integer in the Microsoft .NET Framework 1.0. To correctly identify what each property value means, you can refer to the C++ property tag constants.

MORE INFORMATION

The PropertyItem.Id property is identified by a numeric constant referred to as a property tag. These constants are defined in unmanaged C++. To correctly identify the meaning of a PropertyItem.Id property in your managed code, you can refer to the Graphics Device Interface Plus (GDI+) property tag constants. For a complete list of the property tag constants, visit the following MSDN Web site:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdicpp/GDIPlus/GDIPlusreference/constants/imagepropertytagconstants/propertytagsinalphabeticalorder.asp