// attaches the navigation property of a child back to its parent (if exists)
public static void AttachCyclicNavigationProperty(DbContext db, object parent, object child)
{
if (parent == null || child == null)
{
return;
}
var parentType = ObjectContext.GetObjectType(parent.GetType());
var childType = ObjectContext.GetObjectType(child.GetType());
var objectContext = ((System.Data.Entity.Infrastructure.IObjectContextAdapter)db).ObjectContext;
MethodInfo m = objectContext.GetType().GetMethod("CreateObjectSet", new Type[] { });
MethodInfo generic = m.MakeGenericMethod(childType);
object set = generic.Invoke(objectContext, null);
PropertyInfo entitySetPI = set.GetType().GetProperty("EntitySet");
System.Data.Metadata.Edm.EntitySet entitySet = (System.Data.Metadata.Edm.EntitySet)entitySetPI.GetValue(set, null);
foreach (var prop in entitySet.ElementType.NavigationProperties)
{
if (prop.TypeUsage.EdmType.Name == parentType.Name)
{
var propInfo = childType.GetProperty(prop.Name);
propInfo.SetValue(child, parent, null);
break;
}
}
}
// Gets the primary key fields for an entity type.
public static IEnumerable <PropertyInfo> GetKeysFor(this DbContext db, Type entityType)
{
var objectContext = ((System.Data.Entity.Infrastructure.IObjectContextAdapter)db).ObjectContext;
MethodInfo m = objectContext.GetType().GetMethod("CreateObjectSet", new Type[] { });
MethodInfo generic = m.MakeGenericMethod(entityType);
object set = generic.Invoke(objectContext, null);
PropertyInfo entitySetPI = set.GetType().GetProperty("EntitySet");
System.Data.Metadata.Edm.EntitySet entitySet = (System.Data.Metadata.Edm.EntitySet)entitySetPI.GetValue(set, null);
foreach (string name in entitySet.ElementType.KeyMembers.Select(k => k.Name))
{
yield return(entityType.GetProperty(name));
}
}
