使用where子句对列表对象进行分组并返回

Question

我想根据List中的where子句获取分组列表。我怎么能这样做以下是示例。

public class OrderUpdate
{

    public string Value { get; set; }
    public int OrderType { get; set; }
    public DateTime? StartDate { get; set; }
    public DateTime? EndDate { get; set; }

    public long OrderId { get; set; }
    public string TrackingId { get; set; }

    public OrderUpdate GetGroupedList()
    {    
        var UpdateList = new List<OrderUpdate>();
        var groupedList = UpdateList.GroupBy(u => u.TrackingId);
        // where OrderType in (1, 2, 3, 4)  and add this in groupedlist 
        // which is objecct of OrderUpdate
        return groupedList;
    }
}

Answer 1

你的例子没有编译。我假设您要按TrackId订购列表并过滤某些订单类型。

public IEnumerable<OrderUpdate> GetList()
{
   var validOrderTypes = new[] {1, 2, 3, 4};
   var UpdateList = new List<OrderUpdate>();
   // TODO: fill the list

   return UpdateList
     .Where(u => validOrderTypes.Contains(u.OrderType))
     .OrderBy(u => u.TrackId);
}