internal static List <string> Gather(Expression ex)
{
ColumnNamedGatherer gatherer = new ColumnNamedGatherer();
gatherer.Visit(ex);
return(gatherer.columnNames);
}
// end mike
private Expression ExecuteProjection(ProjectionExpression projection, bool okayToDefer)
{
okayToDefer &= (receivingMember != null && policy.IsDeferLoaded(receivingMember));
// parameterize query
projection = (ProjectionExpression)policy.Mapping.Language.Parameterize(projection);
if (scope != null)
{
// also convert references to outer alias to named values! these become SQL parameters too
projection = (ProjectionExpression)OuterParameterizer.Parameterize(scope.Alias, projection);
}
var saveScope = scope;
ParameterExpression reader = Expression.Parameter(typeof(DbDataReader), "r" + nReaders++);
scope = new Scope(scope, reader, projection.Source.Alias, projection.Source.Columns);
LambdaExpression projector = Expression.Lambda(Visit(projection.Projector), reader);
scope = saveScope;
List <string> columnNames = ColumnNamedGatherer.Gather(projector.Body); //mike
string commandText = policy.Mapping.Language.Format(projection.Source);
var namedValues = NamedValueGatherer.Gather(projection.Source);
var names = namedValues.Select(v => v.Name).ToArray();
Expression[] values = namedValues.Select(v => Expression.Convert(
v.ParameterBindingAction != null ? v.ParameterBindingAction((ConstantExpression)v.Value) : Visit(v.Value),
typeof(object))).ToArray();
string methExecute = okayToDefer
? "ExecuteDeferred"
: "Execute";
if (okayToDefer)
{
}
// call low-level execute directly on supplied DbQueryProvider
Expression result = Expression.Call(provider, methExecute, new[] { projector.Body.Type },
Expression.New(
typeof(QueryCommand <>).MakeGenericType(projector.Body.Type).
GetConstructors()[0],
Expression.Constant(commandText),
Expression.Constant(names),
projector, Expression.Constant(columnNames)
),
Expression.NewArrayInit(typeof(object), values)
);
if (projection.Aggregator != null)
{
// apply aggregator
result = DbExpressionReplacer.Replace(projection.Aggregator.Body, projection.Aggregator.Parameters[0],
result);
}
return(result);
}
