Expression MakeAggregatingProjection(Expression target, Type groupingType, AnonTypeFacade groupKeyTypeFacade)
{
var param = Expression.Parameter(groupingType, "g");
var groupCount = groupKeyTypeFacade.MemberCount;
var projectionExprList = new List <Expression> {
Expression.Call(typeof(Enumerable), nameof(Enumerable.Count), new[] { ItemType }, param)
};
for (var i = 0; i < groupCount; i++)
{
projectionExprList.Add(groupKeyTypeFacade.CreateMemberAccessor(Expression.Property(param, "Key"), i));
}
projectionExprList.AddRange(MakeAggregates(param, _totalSummary));
if (groupCount > 0)
{
projectionExprList.AddRange(MakeAggregates(param, _groupSummary));
}
var projectionTypeFacade = new AnonTypeFacade(projectionExprList);
var projectionLambda = Expression.Lambda(projectionTypeFacade.CreateNewExpression(_anonTypeNewTweaks), param);
return(Expression.Call(typeof(Queryable), nameof(Queryable.Select), new[] { param.Type, projectionLambda.ReturnType }, target, Expression.Quote(projectionLambda)));
}
public Expression Compile(Expression target)
{
var groupByParam = CreateItemParam();
var groupKeyExprList = new List <Expression>();
var descendingList = new List <bool>();
if (_grouping != null)
{
foreach (var i in _grouping)
{
var selectorExpr = String.IsNullOrEmpty(i.GroupInterval)
? CompileAccessorExpression(groupByParam, i.Selector, liftToNullable: true)
: CompileGroupInterval(groupByParam, i.Selector, i.GroupInterval);
groupKeyExprList.Add(selectorExpr);
descendingList.Add(i.Desc);
}
}
var groupKeyTypeFacade = new AnonTypeFacade(groupKeyExprList);
var groupKeyLambda = Expression.Lambda(groupKeyTypeFacade.CreateNewExpression(_anonTypeNewTweaks), groupByParam);
var groupingType = typeof(IGrouping <,>).MakeGenericType(groupKeyLambda.ReturnType, ItemType);
target = Expression.Call(typeof(Queryable), nameof(Queryable.GroupBy), new[] { ItemType, groupKeyLambda.ReturnType }, target, Expression.Quote(groupKeyLambda));
for (var i = 0; i < groupKeyExprList.Count; i++)
{
var orderParam = Expression.Parameter(groupingType, "g");
var orderAccessor = groupKeyTypeFacade.CreateMemberAccessor(
Expression.Property(orderParam, "Key"),
i
);
target = Expression.Call(
typeof(Queryable),
Utils.GetSortMethod(i == 0, descendingList[i]),
new[] { groupingType, orderAccessor.Type },
target,
Expression.Quote(Expression.Lambda(orderAccessor, orderParam))
);
}
return(MakeAggregatingProjection(target, groupingType, groupKeyTypeFacade));
}
