public override async Task <K> AggregateFieldAsync <K>(Expression <Func <T, K> > expression, CancellationToken cancellationToken = default)
{
var model = LambdaExpressionExtend.CreateAggregateModel(expression);
model.OnlyAggregate = true;
var region = new Region(0, 1);
var queryCommand = _context.Database.QueryDynamicAggregate(_context, model, _query, null, _order, region);
var target = await _context.QueryDataDefineSingleAsync <K>(model.OutputDataMapping, _level, queryCommand.Command, queryCommand.InnerPage? 0 : region.Start, queryCommand.State, null, cancellationToken);
if (target == null)
{
var obj = model.OutputDataMapping.InitialData();
target = (K)obj;
}
return(target);
}
public override K AggregateField <K>(Expression <Func <T, K> > expression)
{
AggregateModel model = LambdaExpressionExtend.CreateAggregateModel(expression);
model.OnlyAggregate = true;
Region region = new Region(0, 1);
//target = _context.QueryDynamicAggregateSingle<K>(model, _query, null, _order, region, _level, null);
QueryCommand queryCommand = _context.Database.QueryDynamicAggregate(_context, model, _query, null, _order, region);
K target = _context.QueryDataDefineSingle <K>(model.OutputMapping, _level, queryCommand.Command, queryCommand.InnerPage ? 0 : region.Start, queryCommand.State, null);
if (target == null)
{
object obj = model.OutputMapping.InitialData();
target = (K)obj;
}
return(target);
}