在C＃中的几个foreach循环中执行SQLite插入？

Question

这是我的代码我有：

我读过设置CommandText应该只发生一次，而不是在一个循环中...但是，我如何从foreach中获取单独的项目数据？

有人聪明地重构代码，这将是不错的:)

using (SQLiteTransaction trans = DataAccess.ConnectionManager.BeginTransaction()) 
{ 
    using (SQLiteCommand com = new SQLiteCommand(DataAccess.ConnectionManager)) 
    { 
     // How can I add the parameters here if they are only known in the foreach loop? 
     com.Parameters.Add(new SQLiteParameter("@date", day.SchooldayDate)); 
     com.Parameters.Add(new SQLiteParameter("@periodnumber", period.PeriodNumber)); 
     com.Parameters.Add(new SQLiteParameter("@schoolclasscode", period.SchoolclassCode)); 


     foreach (var week in weekList) 
     { 
      foreach (var day in week.Days) 
      { 
       foreach (var period in day.Periods) 
       { 
        com.CommandText = "Insert into tablename (date,periodnumber,schoolclasscode) Values (@date,@periodnumber,@schoolclasscode)"; 

       } 
      } 
     } 

     com.ExecuteNonQuery(); 
    } 
    trans.Commit();     
} 

UPDATE：该解决方案！

using (SQLiteTransaction trans = DataAccess.ConnectionManager.BeginTransaction()) 
      { 
       using (SQLiteCommand com = new SQLiteCommand(DataAccess.ConnectionManager)) 
       { 
        com.CommandText = "Insert into lessonday (lessondate,lessonnumber,schoolclasscode) VALUES (@lessondate,@lessonnumber,@schoolclasscode)"; 

        SQLiteParameter p1 = new SQLiteParameter("@lessondate", DbType.DateTime); 
        SQLiteParameter p2 = new SQLiteParameter("@lessonnumber", DbType.Int32); 
        SQLiteParameter p3 = new SQLiteParameter("@schoolclasscode", DbType.String); 

        com.Parameters.Add(p1); 
        com.Parameters.Add(p2); 
        com.Parameters.Add(p3); 

        foreach (var week in weekList) 
        { 
         foreach (var day in week.Days) 
         { 
          p1.Value = day.SchooldayDate; 
          foreach (var period in day.Periods) 
          { 
           p2.Value = period.PeriodNumber; 
           p3.Value = period.SchooclassCode; 

           com.ExecuteNonQuery(); 
          } 
         } 
        } 
       } 
       trans.Commit(); 
      } 
     } 

Answer 1

好吧，你可以只移动循环：

using (SQLiteTransaction trans = DataAccess.ConnectionManager.BeginTransaction()) 
{ 
    foreach (var week in weekList) 
    { 
    foreach (var day in week.Days) 
    { 
     foreach (var period in day.Periods) 
     { 
     using (SQLiteCommand com = new SQLiteCommand(...)) 
     { 
      com.Parameters.Add(new SQLiteParameter(...)); 
      com.Parameters.Add(new SQLiteParameter(...)); 
      com.Parameters.Add(new SQLiteParameter(...)); 
      com.CommandText = "Insert into ..."; 
      com.ExecuteNonQuery(); 
     } 
     } 
    } 
    } 
    trans.Commit();     
} 

然而，这似乎有点丑陋的我。我不知道SQLite提供程序将如何表现，但我认为至少值得尝试创建SQLiteCommand根据您的原始代码，添加参数但不是它们的值 ...然后移动ExecuteNonQuery代码进入最内部的foreach循环。事情是这样的：

using (SQLiteTransaction trans = DataAccess.ConnectionManager.BeginTransaction()) 
{ 
    using (SQLiteCommand com = new SQLiteCommand(DataAccess.ConnectionManager)) 
    { 
    com.CommandText = "Insert into ..."; 
    SQLiteParameter p1 = com.Parameters.Add(new SQLiteParameter(...)); 
    SQLiteParameter p2 = com.Parameters.Add(new SQLiteParameter(...)); 
    SQLiteParameter p3 = com.Parameters.Add(new SQLiteParameter(...)); 
    foreach (var week in weekList) 
    { 
     p1.Value = week; 
     foreach (var day in week.Days) 
     { 
     p2.Value = day; 
     foreach (var period in day.Periods) 
     { 
      p3.Value = period;    
      com.ExecuteNonQuery(); 
     } 
     } 
    } 
    } 
    trans.Commit();     
} 

只是重申，我不知道这是否会工作 - 但我希望它会。