在做项目时，要求在同一个GridView中同时显示不同分组中的前若干条数据
几个技术要点：
1、数据分组，本方法中未用group by
2、几个结果格式相同的查询合并绑定
3、取查询结果的前或后若干条数据
public int BindLiftData()
{
int count = 0;
using (MySqlConnection conn = new MySqlConnection(dbServer))
{
FrDData db = new FrDData(conn);
List<int> ids = new List<int>();
var item = from i in db.Items
join p in db.ProgS on i.ProgID equals p.ID
where p.State == 1 && i.Type == "升程"
select new {i.ID};
bool isFirst = true;
int firstID =0;
foreach (var i in item)
{
if (isFirst)
{
firstID = i.ID;
isFirst = false;
}
else
ids.Add(i.ID);
}
var q = (from i in db.Items
join l in db.Lifts on i.ID equals l.ItemID
where i.ID == firstID
orderby l.ID descending
select new { i.ID, i.Name, l.Angle, i.Stole, l.Lift }).Take(3).ToList();
foreach(var x in ids)
{
var r = (from i in db.Items
join l in db.Lifts on i.ID equals l.ItemID
where i.ID == x
orderby l.ID descending
select new { i.ID, i.Name, l.Angle, i.Stole, l.Lift }).Take(3).ToList();
q.AddRange(r);
}
gvLift.DataSource = q;
count = q.Count;
}
return count;
}