Some words about TaxonomyField

TaxonomyField Class

The TaxonomyField class is a custom field class that inherits from the SPFieldLookup class. If you set the properties of the TaxonomyField class, call the Update() method for changes to take effect in the database.

The TaxonomyFieldValue class contains the field value for the TaxonomyField class.

Either the TaxonomyFieldControl object or the TaxonomyWebTaggingControl object server controls can render a TaxonomyField object.

TaxonomyField.GetWssIdsOfTerm Method

Some words about TaxonomyFieldValue and its WssId property.

How to create WssId for terms that are not yet referenced from the site.
How to handle unused Managed Metadata Terms without a WssId?
Update taxonomy field values in a list item through SharePoint web services.