無論如何，我可以將這段代碼優化得更短嗎？

Question

無論如何，我可以將此代碼優化為更短嗎？ MakeList，TrimList等是列表類型。 和車輛是模型。 我的問題是代碼很長。 我在模型中有20個屬性。

---

if (MakeList?.Any() == true)
{
    bidVehicles = bidVehicles.Where(b => MakeList.Contains(b.Vehicle.Make));
}
if (TrimList?.Any() == true)
{
    bidVehicles = bidVehicles.Where(b => TrimList.Contains(b.Vehicle.Trim));
}
if (ModelList?.Any() == true)
{
    bidVehicles = bidVehicles.Where(b => ModelList.Contains(b.Vehicle.Model));
}
if (StockNoList?.Any() == true)
{
    bidVehicles = bidVehicles.Where(b => StockNoList.Contains(b.Vehicle.StockNo));
}
if (BodyStyleList?.Any() == true)
{
    bidVehicles = bidVehicles.Where(b => BodyStyleList.Contains(b.Vehicle.Body));
}
if (ExtColorList?.Any() == true)
{
    bidVehicles = bidVehicles.Where(b => ExtColorList.Contains(b.Vehicle.Exterior));
}

return bidVehicles;

Answer 1

對於LINQ to Objects：

public static class FilterExt
{
    public static IEnumerable<TItem> ApplyFilter<TProp, TItem>(this IEnumerable<TItem> list, List<TProp> filter, Func<TItem, TProp> prop)
    {
        if (filter == null || filter.Count == 0)
        {
            return list;
        }

        return list.Where(x => filter.Contains(prop.Invoke(x)));
    }
}

...

var filtered = bidVehicles
    .ApplyFilter(MakeList, x => x.Vehicle.Make)
    .ApplyFilter(TrimList, x => x.Vehicle.Trim).ToList();

如果使用EF（表示bidVehicles是IQueryable ），則必須為每個屬性編寫表達式，因為您需要完整的謂詞Expression<Func<BidVehicle, bool>>而不是Func<BidVehicle, TProp> 。