private (NavigationExpansionExpression navigationExpression, Expression nullKeyExpression) CreateNullComparisonArguments(
NavigationBindingExpression navigationBindingExpression,
NavigationExpansionExpression navigationExpansionExpression)
{
var navigationKeyAccessExpression = NavigationExpansionHelpers.CreateKeyAccessExpression(
navigationBindingExpression,
new[] { navigationBindingExpression.EntityType.FindPrimaryKey().Properties.First() },
addNullCheck: true);
var nullKeyExpression = NavigationExpansionHelpers.CreateNullKeyExpression(
navigationKeyAccessExpression.Type,
keyCount: 1);
var newNavigationExpansionExpressionState = new NavigationExpansionExpressionState(
navigationExpansionExpression.State.CurrentParameter,
navigationExpansionExpression.State.SourceMappings,
Expression.Lambda(navigationKeyAccessExpression, navigationExpansionExpression.State.PendingSelector.Parameters[0]),
applyPendingSelector: true,
navigationExpansionExpression.State.PendingOrderings,
navigationExpansionExpression.State.PendingIncludeChain,
// we need to remap cardinality reducing operator since it's source type has now changed
navigationExpansionExpression.State.PendingCardinalityReducingOperator?.GetGenericMethodDefinition().MakeGenericMethod(navigationKeyAccessExpression.Type),
navigationExpansionExpression.State.CustomRootMappings,
navigationExpansionExpression.State.MaterializeCollectionNavigation);
var navigationExpression = new NavigationExpansionExpression(
navigationExpansionExpression.Operand,
newNavigationExpansionExpressionState,
navigationKeyAccessExpression.Type);
return(navigationExpression, nullKeyExpression);
}
private NavigationBindingExpression CreateParentBindingExpression(NavigationBindingExpression navigationBindingExpression)
{
// TODO: verify this is correct in all cases
var parentNavigationEntityType = navigationBindingExpression.NavigationTreeNode.Navigation.FindInverse().GetTargetType();
var parentTreeNode = navigationBindingExpression.NavigationTreeNode.Parent;
parentTreeNode.Children.Remove(navigationBindingExpression.NavigationTreeNode);
return(new NavigationBindingExpression(
navigationBindingExpression.RootParameter,
parentTreeNode,
parentNavigationEntityType,
navigationBindingExpression.SourceMapping,
parentNavigationEntityType.ClrType));
}
public static Expression CreateCollectionNavigationExpression(
NavigationTreeNode navigationTreeNode, ParameterExpression rootParameter, SourceMapping sourceMapping)
{
var collectionEntityType = navigationTreeNode.Navigation.ForeignKey.DeclaringEntityType;
Expression operand;
if (navigationTreeNode.IncludeState == NavigationState.Pending ||
navigationTreeNode.ExpansionState == NavigationState.Pending)
{
var entityQueryable = (Expression)NullAsyncQueryProvider.Instance.CreateEntityQueryableExpression(collectionEntityType.ClrType);
var outerBinding = new NavigationBindingExpression(
rootParameter,
navigationTreeNode.Parent,
navigationTreeNode.Navigation.DeclaringEntityType,
sourceMapping,
navigationTreeNode.Navigation.DeclaringEntityType.ClrType);
var outerKeyAccess = NavigationExpansionHelpers.CreateKeyAccessExpression(
outerBinding,
navigationTreeNode.Navigation.ForeignKey.PrincipalKey.Properties,
addNullCheck: outerBinding.NavigationTreeNode.Optional);
var collectionCurrentParameter = Expression.Parameter(
collectionEntityType.ClrType, collectionEntityType.ClrType.GenerateParameterName());
var innerKeyAccess = NavigationExpansionHelpers.CreateKeyAccessExpression(
collectionCurrentParameter,
navigationTreeNode.Navigation.ForeignKey.Properties);
var predicate = Expression.Lambda(
CreateKeyComparisonExpressionForCollectionNavigationSubquery(
outerKeyAccess,
innerKeyAccess,
outerBinding),
collectionCurrentParameter);
operand = Expression.Call(
LinqMethodHelpers.QueryableWhereMethodInfo.MakeGenericMethod(collectionEntityType.ClrType),
entityQueryable,
predicate);
}
else
{
operand = new NavigationBindingExpression(
rootParameter,
navigationTreeNode,
collectionEntityType,
sourceMapping,
collectionEntityType.ClrType);
}
var result = NavigationExpansionHelpers.CreateNavigationExpansionRoot(
operand, collectionEntityType, navigationTreeNode.Navigation);
// this is needed for cases like: root.Include(r => r.Collection).ThenInclude(c => c.Reference).Select(r => r.Collection)
// result should be elements of the collection navigation with their 'Reference' included
var newSourceMapping = result.State.SourceMappings.Single();
IncludeHelpers.CopyIncludeInformation(navigationTreeNode, newSourceMapping.NavigationTree, newSourceMapping);
return(result);
}