private Expression Expand(Expression source, MemberIdentity member)
{
Type convertedType = null;
if (source is UnaryExpression unaryExpression &&
unaryExpression.NodeType == ExpressionType.Convert)
{
source = unaryExpression.Operand;
if (unaryExpression.Type != typeof(object))
{
convertedType = unaryExpression.Type;
}
}
if (source is EntityShaperExpression entityShaperExpression)
{
var entityType = entityShaperExpression.EntityType;
if (convertedType != null)
{
entityType = entityType.RootType().GetDerivedTypesInclusive()
.FirstOrDefault(et => et.ClrType == convertedType);
if (entityType == null)
{
return(null);
}
}
var navigation = member.MemberInfo != null
? entityType.FindNavigation(member.MemberInfo)
: entityType.FindNavigation(member.Name);
if (navigation != null &&
navigation.ForeignKey.IsOwnership)
{
if (navigation.IsCollection())
{
return(CreateShapedQueryExpression(
navigation.GetTargetType(),
_sqlExpressionFactory.Select(navigation.GetTargetType())));
}
var entityProjectionExpression = (EntityProjectionExpression)
(entityShaperExpression.ValueBufferExpression is ProjectionBindingExpression projectionBindingExpression
? _selectExpression.GetMappedProjection(projectionBindingExpression.ProjectionMember)
: entityShaperExpression.ValueBufferExpression);
var innerShaper = entityProjectionExpression.BindNavigation(navigation);
if (innerShaper == null)
{
var targetEntityType = navigation.GetTargetType();
var innerSelectExpression = _sqlExpressionFactory.Select(targetEntityType);
var innerShapedQuery = CreateShapedQueryExpression(targetEntityType, innerSelectExpression);
var makeNullable = navigation.ForeignKey.PrincipalKey.Properties
.Concat(navigation.ForeignKey.Properties)
.Select(p => p.ClrType)
.Any(t => t.IsNullableType());
var outerKey = CreateKeyAccessExpression(
entityShaperExpression, navigation.ForeignKey.PrincipalKey.Properties, makeNullable);
var innerKey = CreateKeyAccessExpression(
innerShapedQuery.ShaperExpression, navigation.ForeignKey.Properties, makeNullable);
var joinPredicate = _sqlTranslator.Translate(Expression.Equal(outerKey, innerKey));
_selectExpression.AddLeftJoin(innerSelectExpression, joinPredicate, null);
var leftJoinTable = ((LeftJoinExpression)_selectExpression.Tables.Last()).Table;
innerShaper = new EntityShaperExpression(targetEntityType,
new EntityProjectionExpression(targetEntityType, leftJoinTable, true),
true);
entityProjectionExpression.AddNavigationBinding(navigation, innerShaper);
}
return(innerShaper);
}
}
return(null);
}