At run time, the ASP.NET compilation system uses the information specified in the profile section of the configuration file to generate a class called ProfileCommon, which is derived from System.Web.Profile.ProfileBase. The class allows you to access and modify the values for individual user profiles.

The ProfileCommon class definition is based on the properties defined in the properties subsection of the profile section of the configuration file. The property values that you specify for an instance of the System.Web.Configuration.ProfilePropertySettings class will be used to define an associated property in the ProfileCommon class.

The default value is used as the initial value for the associated ProfileCommon class property when an individual user profile does not contain a value for the property. The ProfilePropertySettings.DefaultValue property may be a string value, an XML-encoded value (serialization mode for the property is XML serialization) or a base-64-encoded binary string (if the serialization mode for the property is binary serialization).