protected override Expression VisitChildren(ExpressionVisitor visitor)
{
var changed = false;
var projections = new List <ProjectionExpression>();
IDictionary <ProjectionMember, Expression> projectionMapping;
if (Projection.Any())
{
projectionMapping = _projectionMapping;
foreach (var item in Projection)
{
var projection = (ProjectionExpression)visitor.Visit(item);
projections.Add(projection);
changed |= projection != item;
}
}
else
{
projectionMapping = new Dictionary <ProjectionMember, Expression>();
foreach (var mapping in _projectionMapping)
{
var newProjection = visitor.Visit(mapping.Value);
changed |= newProjection != mapping.Value;
projectionMapping[mapping.Key] = newProjection;
}
}
var fromExpression = (RootReferenceExpression)visitor.Visit(FromExpression);
changed |= fromExpression != FromExpression;
var predicate = (SqlExpression)visitor.Visit(Predicate);
changed |= predicate != Predicate;
var orderings = new List <OrderingExpression>();
foreach (var ordering in _orderings)
{
var orderingExpression = (SqlExpression)visitor.Visit(ordering.Expression);
changed |= orderingExpression != ordering.Expression;
orderings.Add(ordering.Update(orderingExpression));
}
var offset = (SqlExpression)visitor.Visit(Offset);
changed |= offset != Offset;
var limit = (SqlExpression)visitor.Visit(Limit);
changed |= limit != Limit;
if (changed)
{
var newSelectExpression = new SelectExpression(projections, fromExpression, orderings)
{
_projectionMapping = projectionMapping,
Predicate = predicate,
Offset = offset,
Limit = limit,
IsDistinct = IsDistinct
};
return(newSelectExpression);
}
return(this);
}
protected abstract Expression VisitSelect(SelectExpression selectExpression);
