c# - Linq SELECT 与 ExecuteQuery

Question

我得到错误:

The type 'System.Int32[]' must declare a default (parameterless) constructor in order to be constructed during mapping.

代码:

var gamePlayRecord = db.ExecuteQuery<int[]>("SELECT UserID, IPID, GameID FROM ArcadeGames WHERE ID = " + gamePlayRecordID).Single();
var userID = gamePlayRecord[0];
var ipID = gamePlayRecord[1];
var gameID = gamePlayRecord[2];

我知道这是错误的，但是有人可以告诉我如何在不需要创建新对象的情况下正确地做到这一点吗？

Answer 1

这个查询的结果不是int[]而是一行数字。

不好的解决方案:对每个数字使用:

int userID = db.ExecuteQuery<int>("SELECT UserID FROM ArcadeGames WHERE ID = " + gamePlayRecordID).Single();
int ipID = db.ExecuteQuery<int>("SELECT IPID FROM ArcadeGames WHERE ID = " + gamePlayRecordID).Single();
int gameID db.ExecuteQuery<int>("SELECT GameID FROM ArcadeGames WHERE ID = " + gamePlayRecordID).Single();

或者创建sql查询

db.ExecuteQuery<int>(@"
SELECT UserID FROM ArcadeGames WHERE ID = {0}
UNION ALL
SELECT IPID FROM ArcadeGames WHERE ID = {0}
UNION ALL
SELECT GameID FROM ArcadeGames WHERE ID = {0}", 
gamePlayRecordID).ToList();

或者创建类...