Gets or sets whether this class member represents a column that is part or all of the primary key of the table.
Assembly: System.Data.Linq (in System.Data.Linq.dll)
Assuming an entity class, you must provide at least one member with this attribute, and it must be mapped to the primary key or a unique key in the corresponding table or view. Failure to do this prompts LINQ to SQL to consider instances of the class as read-only for submitting changes to the database.
If you designate more than one member of the class by using this property, the key is said to be a composite of the associated columns.
LINQ to SQL does not support computed columns as primary keys.
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.