使Linq to SQL干燥

我迅速地戳了一下。可能不会编译(尤其是“来自团队中的团队”),但您可以考虑返回iqueryable<>。但是,您的iqueryable返回一个匿名类型,这不起作用。因此,您可能需要创建一个显式类型来代替“select new teamstable,solutionsTable.solutionname”

    public List<TeamBE> GetTeamsBySolutionID(int solutionID)
    {
        Esadmin db = new Esadmin(_connectionString);
        return GetTeamsBy(db, _GetTeamsBySolutionID(db, solutionID));
    }

    IQueryable<Team> _GetTeamsBySolutionID(Esadmin db, int solutionID)
    {
        return from teamsTable in db.Teams
               where teamsTable.SolutionID == SolutionID
               select teamsTable;
    }

    List<TeamBE> GetTeamsBy(Esadmin db, IQueryable<Team> teams)
    {
        List<TeamBE> teams = new List<TeamBE>();

        var qry = (from teamsTable in teams
                   join solutionsTable in db.Solutions on teamsTable.SolutionID equals solutionsTable.SolutionID
                   select new { teamsTable, solutionsTable.SolutionName });

        foreach (var result in qry)
        {
            TeamBE team = new TeamBE();

            team.TeamID = result.teamsTable.TeamID;
            team.Description = result.teamsTable.Description;
            team.Status = result.teamsTable.Status;
            team.LastModified = result.teamsTable.LastModified;
            team.SolutionID = result.teamsTable.SolutionID;
            team.SolutionName = result.SolutionName;
            team.Name = result.teamsTable.Name;
            team.LocationLevel = result.teamsTable.LocationLevel;
            team.AORDriven = result.teamsTable.AoRDriven;
            team.CriteriaID = result.teamsTable.CriteriaID ?? Guid.Empty;

            teams.Add(team);
        }
        return teams;
    }

我想你可以申报 qry 变量AS IEnumerable<YourDataTypeEntity> 把它传递给一个方法。我喜欢作为一个建设者来做:

class MyDataType
{
  public MyDataType() {}
  public MyDataType(MyDataTypeEntity mdte)
  {
    // set properties and fields here
  }

  // ...
}

当你想处理结果的时候,你可以发出一个iquerier,然后你对结果进行修正。我不确定这是不是你要问的那种事情,还是我对你的问题有点不知所措。

也可以看看 AutoMapper ,该API使用基于约定的匹配算法将对象中的源值与目标值进行匹配。使用它可能会删除大部分A=B.C代码。

我用EntityFramework实现了类似这样的事情:

//This returns an IQueryable of your Linq2Sql entities, here you put your query.
protected IQueryable<Team> GetTeamByIdQuery(Guid teamID)
{
    var qry = (from TeamsTable in db.Teams
               where blablabla.....
               select Teams;

    return qry;
}


//This will return your real entity
public IList<TeamBE> GetTeamById(Guid teamID)
{
    var query = this.GetTeamByIdQuery(teamID);
    IList<TeamBE> teams = ExecuteTeamQuery(query).toList<TeamBE>();

    return teams;
}


//this method will do the mapping from your L2S entities to your model entities
protected IQueryable<TeamBE> ExcuteTeamQuery(IQueryable<Team> query)
{
    return 
        query.select<Team, TeamBE> (team => 
           new TeamBE
           {
              TeamID = team.TeamID,
              Description = team.Description 
           }

}

还没有测试这么多,但它起作用了。我也在用一种方法来定义基于bitflag参数要加载的属性。我还没开始工作,但会是这样的:

public IQueryable<TeamBE> ExcuteTeamQuery(IQueryable<Team> query, int loadLevel)
{
    return 
        query.select<Team, TeamBE> (team => 
           new TeamBE
           {
              TeamID = team.TeamID,
              TeamMembers = (HaveToLoad(LoadLevel.TeamMembers, loadLevel)) ? team.TeamMembers : null 
           }

}


enter code here

尝试扩展方法: 如果你有

public IQueryable<Team> GetTeams() { return db.Teams; }

尝试写作:

public IQueryable<Team> WithDivisionId(this IQueryable<Team> qry, int divisionId)
{ return (from t in qry where t.DivisionId = divisionId select t);}

这样,您就可以编写多个扩展方法来查询 IQueryable<Team> 把它们分层…

要从1级联赛中获得9场或更多的胜利,并且在某个时刻连续5场或更多,你只需写下:

GetTeams().WithDivisionId(1).HavingWonAtLeast(9).WithWinningStreak(5);