部分代码:
SPList list = web.Lists[Newlistname];//获取列表
SPQuery oQuery = new SPQuery();//执行查询
oQuery.Query = "<OrderBy><FieldRef Name='Modified' Ascending='FALSE'/></OrderBy>";//查询字段
SPListItemCollection collListItems = list.GetItems(oQuery);//获取查询结果
关于<OrderBy>用法参考nsdn:http://msdn.microsoft.com/zh-cn/library/ms467378(v=office.12).aspx