Asp.net mvc 如何将IEnumerable结果转换为列表<；treenode>；

如何在C#、.NET4.0和MVC中获取

IEnumerable

结果并将其转换为

列表

我基本上在两个地方运行相同的查询，只想访问数据库一次。我在很多地方运行了两次这个查询

 using (SqlConnection cn = new SqlConnection(DBUtils._connStr))

 string sql = @"SELECT L.Name as Name, L.LocationTypeID as LocationTypeID, L.LocationID as LocationID, L.ParentLocationID as ParentLocationID, ISNULL(L.OrderByNumber, -10000) as SectionOrder, L.FromAddress as FromAddress,
         lojL.Name as Section, lojL.LocationID as SectionID,
                    ISNULL(lojL.Name + ' \ ','') + L.Name as NameWithSection
                    FROM hdLocations as L
              LEFT OUTER JOIN hdLocations as lojL ON L.ParentLocationID = lojL.LocationID
            WHERE L.LocationID > 0 AND L.InstanceID=0 And L.ParentLocationID =0";
sql += " ORDER BY  L.OrderByNumber, L.Name";

IEnumerable<TicketLocation> locations = cn.Query<TicketLocation>(sql);

---

好的，要将

IEnumerable

转换为

列表

，只需调用

.ToList（）

。就从

TicketLocation

到

TreeNode

的映射而言，您发布的代码有什么问题？您可以通过以下方式大大简化该代码：

var locs = locations.Where(m => m.ParentLocationID == 0 && m.LocationID > 0)
    .Select(m => new TreeNode
        {
            id = m.LocationID,
            data = m.Name,
            parentId = m.ParentLocationID
        }).ToList();

---

这将导致

LOC

成为

列表

什么类型的“cn”？“cn.Query（）”的返回类型是什么？是否要从

IEnumerable

生成

IEnumerable

？cn是SQLConnection…@ClaudioRedi类似的，是的。请参阅我的编辑。我还提到，您还需要有using子句

using System.Linq如果你还没有.Chris的using子句，我就是找不到这个。完美的我对构建TreeNode的代码有点挂念，它有第四个值。Erik，最好像你一样提到“使用”，因为很难找到它！很多人忽略了这一点，也。。。
foreach (TicketLocation TL in locations)
{
    if ((TL.ParentLocationID == 0) && (TL.LocationID > 0))
    {
        TreeNode itemTreeNode = new TreeNode()
        {
            id = TL.LocationID,
            data = TL.Name,
        };
        itemTreeNode.id = TL.LocationID;
        itemTreeNode.data = TL.Name;
        itemTreeNode.parentId = TL.ParentLocationID;
        // itemTreeNode.

        locs.Add(itemTreeNode);
    }
}

var locs = locations.Where(m => m.ParentLocationID == 0 && m.LocationID > 0)
    .Select(m => new TreeNode
        {
            id = m.LocationID,
            data = m.Name,
            parentId = m.ParentLocationID
        }).ToList();