在C＃中的幾個foreach循環中執行SQLite插入？

Question

這是我的代碼我有：

我讀過設置CommandText應該只發生一次，而不是在一個循環中...但是，我如何從foreach中獲取單獨的項目數據？

有人聰明地重構代碼，這將是不錯的:)

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：該解決方案！

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，你可以只移動循環：

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，這似乎有點醜陋的我。我不知道SQLite提供程序將如何表現，但我認爲至少值得嘗試創建SQLiteCommand根據您的原始代碼，添加參數但不是它們的值 ...然後移動ExecuteNonQuery代碼進入最內部的foreach循環。事情是這樣的：

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，我不知道這是否會工作 - 但我希望它會。