c# - 单个 sqlconnection 中的多个 sqltransactions

Question

我有一些代码要执行如下。但是我在第二次迭代中不断收到异常“此 SqlTransaction 已完成；它不再可用”。有人可以帮我指出我在这里做错了什么吗？谢谢!

    SqlConnection cn = (SqlConnection)SqlConnectionManager.Instance.GetUserConnection(user);
 cn.Open();
 try
 {
    foreach (Master mRecord in masterList)
  {
   if (sqlTransaction == null)
       sqlTransaction = cn.BeginTransaction();
   SqlCommand cm = cn.CreateCommand();
   cm.Transaction = sqlTransaction;
   cm.CommandType = CommandType.StoredProcedure;
   cm.CommandText = "pr_InsertRecords";
       try
   {
    cm.ExecuteNonQuery();
    Debug.WriteLine("Auditor.Write: end sql table value param");
    sqlTransaction.Commit();
    sqlTransaction.Dispose();
   }
   catch (Exception Ex)
   {
    Debug.WriteLine(" Exception message: " + Ex.Message);
    if (Ex.InnerException != null)
    {
     Debug.WriteLine("Inner exception message" + Ex.InnerException.Message);
    }
    sqlTransaction.Rollback();
   }
  }
 }
 finally
 {
        cn.Close();
      }

Answer 1

在循环中，您可以提交或回滚，但不会将引用重置为 null。 SqlTransaction 通常不这样使用，而是在 using() block 中使用，就像 SqlConnection 是:

using (SqlConnection cn = SqlConnectionManager.Instance.GetUserConnection(user)) 
{
  foreach (Master mRecord in masterList)
  {
  try
  {
    using (SqlTransaction sqlTransaction = cn.BeginTransaction()) 
    {
      using (SqlCommand cm = cn.CreateCommand()) 
      {
        cm.Transaction = sqlTransaction;
        cm.CommandType = CommandType.StoredProcedure;
        cm.CommandText = "pr_InsertRecords";
        cm.ExecuteNonQuery();
      }
      sqlTransaction.Commit();
      Debug.WriteLine("Auditor.Write: end sql table value param");
    }
  }
  catch (Exception Ex)
  {
    Debug.WriteLine(" Exception message: " + Ex.Message);
  }
}