How to get the Primary Key(s) in Entity Framework 4.1, i.e. using DbContext

Question

The answers I\'m seeing here are for ObjectContext. Is there a property to determine an entity\'s primary key names when using DbContext?

Ah.. one of those times tha

Answer 1

The solution proposed by Ladislav Mrnka won't work for derived entities as You can't create an object set for a derived type. You'll see this error :

ArgumentException: There are no EntitySets defined for the specified entity type ... If ... is a derived type, use the base type instead. Parameter name: TEntity

Here is my solution avoiding creating an object set :

public string[] GetEntityKeyNames(DbContext context)
{
    if (context == null)
    {
        throw new ArgumentNullException("context");
    }
    var objectContext = ((IObjectContextAdapter)Context).ObjectContext;
    //We must use the namespace of the context and the type name of the entity
    string entityTypeName = context.GetType().Namespace + '.' + typeof(TEntity).Name;
    var entityType = objectContext.MetadataWorkspace.GetItem(entityTypeName, DataSpace.CSpace);
    return entityType.KeyProperties.Select(k => k.Name).ToArray();
}