c＃linq加入列表中的子列表

Question

我有一个列表：var_assets_root，它有一个嵌套的子列表：contents。我可以在根列表上进行连接，并通过对lst_invtypes_assets中的索引项进行两次连接，使用其他两个列表lst_stations_composite_retribution和var_assets_root中的额外项来对其进行扩充。但是我也想对子列表var_assets_root-->contents\b.contents中的项目进行连接，这些项目到目前为止下面的代码没有做到。 Image>>structure of var_assets_root in watch window

mysql mysql_object = new mysql();
  List<mysql.invtypes_asset> lst_invtypes_assets = mysql_object.dbmysql_invtypes_asset_to_list();
  List<mysql.stations_composite_retribution> lst_stations_composite_retribution = mysql_object.dbmysql_select_stastations_composite_retribution_to_list();
  var lst_assets_list = new AssetList("134399", "343434SxSFX7qO81LqUCberhS1OQtktMvARFGED0ZRSN5c4XP230SA", "434367527");
  lst_assets_list.Query();
  var var_assets_root = lst_assets_list.assets.ToList();

  var var_assets_root_typeid_station 
    = from b in var_assets_root
    join c in lst_invtypes_assets on b.typeID equals c.typeID
    join d in lst_stations_composite_retribution on b.locationID equals d.stationID
    select new {b.contents, b.flag, b.itemID, b.locationID, d.solarSystemName, d.security, d.securityClass, d.regionName, b.quantity, b.singleton, b.typeID, c.groupID, c.marketGroupID, c.volume,
      c.typeName, c.description};

我已经为每个内容子列表运行linq查询并相应地分配值。

private void btn_evenet_Click(object sender, EventArgs e)
{
  Stopwatch stopwatch1 = new Stopwatch();
  Stopwatch stopwatch2 = new Stopwatch();
  stopwatch1.Start();
  mysql mysql_object = new mysql();
  List<mysql.invtypes_asset> lst_invtypes_assets = mysql_object.dbmysql_invtypes_asset_to_list();
  List<mysql.stations_composite_retribution> lst_stations_composite_retribution = mysql_object.dbmysql_select_stastations_composite_retribution_to_list();
  AssetList lst_assets_list = new AssetList("2312099", "J&VNM14RFUkSxSFX7qAAAAAA1OQtktMvYTVZZBhkO23235c4Z&HJKODPQLM", "123231527");
  lst_assets_list.Query();
  var var_assets_root = lst_assets_list.assets.ToList();
  var var_assets_root_typeid_station 
    = from b in var_assets_root
    join c in lst_invtypes_assets on b.typeID equals c.typeID
    join d in lst_stations_composite_retribution on b.locationID equals d.stationID
      select new { b.contents, b.flag, b.itemID, b.locationID, d.solarSystemName, d.security, d.securityClass, d.regionName, b.quantity, b.singleton, b.typeID, c.groupID, c.marketGroupID, c.volume,
      c.typeName, c.description};
  var lst_assets_root_typeid_station = var_assets_root_typeid_station.ToList(); // Using .ToArray() is about 200ms faster than .ToList()
  stopwatch2.Start(); 
  for (Int32 a = 0; a < lst_assets_root_typeid_station.Count(); a++)
  {
    if (lst_assets_root_typeid_station[a].contents.Count() >= 0)
    {
      for (Int32 b = 0; b < lst_assets_root_typeid_station[a].contents.Count(); b++)
      {
        var var_row_invtypes_assets = lst_invtypes_assets.Where(x => x.typeID == lst_assets_root_typeid_station[a].contents[b].typeID).ToArray();
        lst_assets_root_typeid_station[a].contents[b].groupID = var_row_invtypes_assets[0].groupID;
        lst_assets_root_typeid_station[a].contents[b].typeName = var_row_invtypes_assets[0].typeName;
        lst_assets_root_typeid_station[a].contents[b].description = var_row_invtypes_assets[0].description;
        lst_assets_root_typeid_station[a].contents[b].volume = var_row_invtypes_assets[0].volume;
        lst_assets_root_typeid_station[a].contents[b].marketGroupID = var_row_invtypes_assets[0].marketGroupID;
        if (lst_assets_root_typeid_station[a].contents[b].contents.Count() != 0)
        {
          for (Int32 c = 0; c < lst_assets_root_typeid_station[a].contents[b].contents.Count(); c++)
          {
            var_row_invtypes_assets = lst_invtypes_assets.Where(x => x.typeID == lst_assets_root_typeid_station[a].contents[b].contents[c].typeID).ToArray();
            lst_assets_root_typeid_station[a].contents[b].contents[c].groupID = var_row_invtypes_assets[0].groupID;
            lst_assets_root_typeid_station[a].contents[b].contents[c].typeName = var_row_invtypes_assets[0].typeName;
            lst_assets_root_typeid_station[a].contents[b].contents[c].description = var_row_invtypes_assets[0].description;
            lst_assets_root_typeid_station[a].contents[b].contents[c].volume = var_row_invtypes_assets[0].volume;
            lst_assets_root_typeid_station[a].contents[b].contents[c].marketGroupID = var_row_invtypes_assets[0].marketGroupID;
          }
        }
      }         
    }
  }
  stopwatch2.Stop();
  stopwatch1.Stop();
  lbl_stopwatch1.Text = "Everything: " +  stopwatch1.Elapsed.ToString("mm\\:ss\\.ff"); // 1.53 seconds no debugging
  lbl_stopwatch2.Text = "contents sublists: " +  stopwatch2.Elapsed.ToString("mm\\:ss\\.ff"); // contents sublists take 1.03 seconds no debugging
}
 }

一旦我认为'yield'在调用getAllContents时从一堆内容节点弹出一个内容节点我调整了我的代码和你的函数，以便现在所有内容节点都被递归并从linq查询填充它们的空值。此外，创建var_assets_root_typeid_station的linq之后的新代码现在几乎快了两倍。谢谢。

private void btn_evenet_Click(object sender, EventArgs e)
{
  Stopwatch stopwatch1 = new Stopwatch();
  Stopwatch stopwatch2 = new Stopwatch();
  stopwatch1.Start();
  mysql mysql_object = new mysql();
  List<mysql.invtypes_asset> lst_invtypes_assets = mysql_object.dbmysql_invtypes_asset_to_list();
  List<mysql.stations_composite_retribution> lst_stations_composite_retribution = mysql_object.dbmysql_select_stastations_composite_retribution_to_list();
  AssetList lst_assets_list = new AssetList("12345678", "ABCDEFFGHIKL01235kokJDSD213123", "12345678");
  lst_assets_list.Query();
  var var_assets_root = lst_assets_list.assets.ToList();
  var var_assets_root_typeid_station 
    = from b in var_assets_root
    join c in lst_invtypes_assets on b.typeID equals c.typeID
    join d in lst_stations_composite_retribution on b.locationID equals d.stationID
      select new 
        {b.contents, b.flag, b.itemID, b.locationID, d.solarSystemName, d.security, d.securityClass, d.regionName, b.quantity, b.singleton, b.typeID, c.groupID, c.marketGroupID, c.volume,
      c.typeName, c.description};
  var lst_assets_root_typeid_station = var_assets_root_typeid_station.ToList(); // Using .ToArray() is about 200ms faster than .ToList()
  stopwatch2.Start(); 
 for (Int32 a = 0; a < lst_assets_root_typeid_station.Count(); a++)
  {
    if (lst_assets_root_typeid_station[a].contents.Count() > 0)
    {
      for (Int32 z = 0; z < lst_assets_root_typeid_station[a].contents.Count(); z++)
      {
        foreach (AssetList.Item contentnode in getAllContents(lst_assets_root_typeid_station[a].contents[z]))
        {
          var var_row_invtypes_assets = lst_invtypes_assets.Where(x => x.typeID == contentnode.typeID).ToArray();
          contentnode.groupID = var_row_invtypes_assets[0].groupID;
          contentnode.typeName = var_row_invtypes_assets[0].typeName;
          contentnode.description = var_row_invtypes_assets[0].description;
          contentnode.volume = var_row_invtypes_assets[0].volume;
          contentnode.marketGroupID = var_row_invtypes_assets[0].marketGroupID;
        }
      }
    }
  }    
  stopwatch2.Stop();
  stopwatch1.Stop();
  lbl_stopwatch1.Text = "Everything: " +  stopwatch1.Elapsed.ToString("mm\\:ss\\.ff"); // 1.16 seconds no debugging
  lbl_stopwatch2.Text = "contents sublists: " +  stopwatch2.Elapsed.ToString("mm\\:ss\\.ff"); // contents sublists take 0.63 seconds no debugging
}

IEnumerable<AssetList.Item> getAllContents(AssetList.Item contentNode)
{
  if (contentNode.contents.Count == 0)
  {
    yield return contentNode;
  }
  else
  {
    foreach (AssetList.Item subContentNode in contentNode.contents)
    {
      yield return subContentNode;
      foreach (AssetList.Item subSubContentNode in getAllContents(subContentNode))
        yield return subSubContentNode;
    }
  }
}

Answer 1

你不只是在寻找SelectMany吗？

var contents = lst_invtypes_assets.contents.SelectMany(x => x.contents);

Answer 2

我认为你得到的是你想要访问外部.contents属性，如果它包含任何contents，那么也可以访问它们，等等......递归地

虽然您可以通过使用Func<AssetList.Item, IEnumerable<AssetList.Item>>定义递归.Aggregate和LINQ行来实现此目的，但定义您自己的递归方法可能更容易/更易读。

IEnumerable<AssetList.Item> getAllContents(AssetList.Item station) {
    foreach (AssetList.Item subStation in station.contents) {
        yield return subStation;
        foreach (AssetList.Item subSubStation in getAllContents(substation))
            yield return subSubStation;
    }
}

然后你可以做一个简单的foreach(var station in getAllContents(parentStation))，或修改它以包含原始电台，使其成为扩展方法等。