private static void Main()
{
SelectQuery.Execute();
JoinQuery.Execute();
GroupByQuery.Execute();
OrderBy.Execute();
SubQuery.Execute();
}
private static void AddGroupByItemWrapper(GroupByQuery groupBy, List <LambdaExpression> elementProjections)
{
var keySelector = groupBy.KeySelector;
var elementSelector = groupBy.ElementSelector;
var keyType = keySelector.Body.Type;
var elementType = elementSelector.Body.Type;
var wrapperType = typeof(GroupByItemWrapper <,>).MakeGenericType(keyType, elementType);
var wrapperKeyProperty = wrapperType.GetProperty("Key");
var wrapperElementProperty = wrapperType.GetProperty("Element");
var projectionParameter = keySelector.Parameters[0];
var projectionLambda = FastExpression.Lambda(
Expression.MemberInit(
Expression.New(wrapperType),
Expression.Bind(wrapperKeyProperty, keySelector.Body),
Expression.Bind(wrapperElementProperty,
elementSelector.BindParameters(projectionParameter))),
projectionParameter);
groupBy.Source = QueryFactory.Select(groupBy.Source, projectionLambda);
var wrapperParameter = Expression.Parameter(wrapperType, "wrapper");
var wrapperKeyAccess = Expression.MakeMemberAccess(wrapperParameter, wrapperKeyProperty);
var wrapperElementAccess = Expression.MakeMemberAccess(wrapperParameter, wrapperElementProperty);
groupBy.KeySelector = FastExpression.Lambda(wrapperKeyAccess, wrapperParameter);
groupBy.ElementSelector = FastExpression.Lambda(wrapperElementAccess, wrapperParameter);
for (int i = 0; i < elementProjections.Count; i++)
{
elementProjections[i] = FastExpression.Lambda(
elementProjections[i].BindParameters(wrapperElementAccess),
wrapperParameter);
}
}
