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

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逝去的感伤 2020-12-29 08:52

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

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Happy的楠姐 (楼主)

2020-12-29 09:42

You cannot use DbContext for that - DbContext API is just dumb wrapper with only most needed functionality. For everything more complex you must convert DbContext back to ObjectContext and use it. Try something like this:

Extract key names:

public static string[] GetEntityKeyNames(this DbContext context) where TEntity : class
{
  if (context == null)
    throw new ArgumentNullException("context");

  var set = ((IObjectContextAdapter)context).ObjectContext.CreateObjectSet();
  var entitySet = set.EntitySet;
  return entitySet.ElementType.KeyMembers.Select(k => k.Name).ToArray();
}

Here's a method that will extract the key values of an entity:

public static IEnumerable