public override DbExpression Visit(DbGroupByExpression expression)
{
EntityUtil.CheckArgumentNull(expression, "expression");
DbExpression result = expression;
DbGroupExpressionBinding newInput = this.VisitGroupExpressionBinding(expression.Input);
this.EnterScope(newInput.Variable);
IList <DbExpression> newKeys = this.VisitExpressionList(expression.Keys);
this.ExitScope();
this.EnterScope(newInput.GroupVariable);
IList <DbAggregate> newAggs = this.VisitList <DbAggregate>(expression.Aggregates, this.VisitAggregate);
this.ExitScope();
if (!object.ReferenceEquals(expression.Input, newInput) ||
!object.ReferenceEquals(expression.Keys, newKeys) ||
!object.ReferenceEquals(expression.Aggregates, newAggs))
{
RowType groupOutput =
TypeHelpers.GetEdmType <RowType>(TypeHelpers.GetEdmType <CollectionType>(expression.ResultType).TypeUsage);
var boundKeys = groupOutput.Properties.Take(newKeys.Count).Select(p => p.Name).Zip(newKeys).ToList();
var boundAggs = groupOutput.Properties.Skip(newKeys.Count).Select(p => p.Name).Zip(newAggs).ToList();
result = CqtBuilder.GroupBy(newInput, boundKeys, boundAggs);
}
NotifyIfChanged(expression, result);
return(result);
}
