protected override Expression VisitMethodCall(MethodCallExpression expr)
{
if (WhereArgumentsVisitor.SupportsMethod(expr.Method.Name))
{
return(VisitCriterionExpression(expr));
}
//TODO: this needs to be refactored...
//create any collection subcriteria and get the collection access expression
MemberNameVisitor memberVisitor = new MemberNameVisitor(_rootCriteria, true);
memberVisitor.Visit(expr.Arguments[0]);
CollectionAccessExpression collectionExpr = (CollectionAccessExpression)memberVisitor.CurrentExpression;
string propertyName = null;
IProjection projection = null;
PropertyProjection currentProjection;
if (expr.Arguments.Count > 1)
{
propertyName = MemberNameVisitor.GetMemberName(_rootCriteria, expr.Arguments[1]);
}
else if ((currentProjection = _rootCriteria.GetProjection() as PropertyProjection) != null)
{
propertyName = currentProjection.PropertyName;
}
switch (expr.Method.Name)
{
case "Average":
projection = NHProjections.Avg(propertyName);
break;
case "Count":
case "LongCount":
if (expr.Arguments.Count > 1)
{
_rootCriteria.Add(WhereArgumentsVisitor.GetCriterion(_rootCriteria, _session, expr.Arguments[1]));
}
if (collectionExpr != null)
{
//get count on collection element's identifier property
propertyName = memberVisitor.MemberName + "." + collectionExpr.ElementExpression.MetaData.IdentifierPropertyName;
projection = NHProjections.Count(propertyName);
}
else
{
projection = NHProjections.RowCount();
}
break;
case "Max":
projection = NHProjections.Max(propertyName);
break;
case "Min":
projection = NHProjections.Min(propertyName);
break;
case "Sum":
projection = NHProjections.Sum(propertyName);
break;
default:
throw new NotImplementedException("The method '" + expr.Method.Name + "' is not implemented.");
}
_projections.Add(projection);
return(expr);
}
/// <summary>
/// A property value sum
/// </summary>
public static AggregateProjection Sum(Expression <Func <object> > expression)
{
return(Projections.Sum(ExpressionProcessor.FindMemberExpression(expression.Body)));
}