的SqlParameter例外：SqlParameter的已被另一SqlParameterCollection包含

Question

我得到一个异常

SqlParameter有已被另一SqlParameterCollection

载我提出我的SqlParameter召唤出foreach循环因为我认为这是问题，但我仍然得到同样的例外。

private void SendToSQLServer_FactionStandings(Faction faction) 
{ 
    string sqlCnnString = "Server=tcp:horde.database.windows.net,1433;Initial Catalog=horde_db;Persist Security Info=False;User ID=USERNAME@horde;Password=PASSWORD;MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;"; 

    SqlParameter sqlParaFaction_Faction_ID = new SqlParameter("@Faction_ID", SqlDbType.Int); 
    SqlParameter sqlParaFaction_ToFactionID = new SqlParameter("@ToFaction_ID", SqlDbType.Int); 
    SqlParameter sqlParaFaction_Standing = new SqlParameter("@Standing", SqlDbType.SmallInt); 

    using (SqlConnection sqlCnn = new SqlConnection(sqlCnnString)) 
    { 
     sqlCnn.Open(); 

     using (SqlTransaction sqlTrans = sqlCnn.BeginTransaction()) 
     { 
      using (SqlCommand sqlCmd = new SqlCommand()) 
      { 
       sqlCmd.Parameters.Clear(); 

       foreach (FactionStanding factionStanding in faction.FactionStandings) 
       { 
        // 
        // - Insert Faction Standing Table Data 
        // 

        sqlParaFaction_Faction_ID.Value = factionStanding.Faction_ID; 
        sqlCmd.Parameters.Add(sqlParaFaction_Faction_ID); // <---- Getting exception here 

        sqlParaFaction_ToFactionID.Value = factionStanding.ToFaction_ID; 
        sqlCmd.Parameters.Add(sqlParaFaction_ToFactionID); 

        sqlParaFaction_Standing.Value = factionStanding.DefaultStanding; 
        sqlCmd.Parameters.Add(sqlParaFaction_Standing); 

        string sqlCmdFactionStandings = "INSERT INTO FactionStandings (Faction_ID, ToFaction_ID, Standing) VALUES (@Faction_ID, @ToFaction_ID, @Standing)"; 

        sqlCmd.Connection = sqlCnn; 
        sqlCmd.CommandText = sqlCmdFactionStandings; 
        sqlCmd.Transaction = sqlTrans; 

        sqlCmd.ExecuteNonQuery(); 
       } 

       sqlTrans.Commit(); 
       sqlCmd.Parameters.Clear(); 
      } 
     } 
    } 
} 

Answer 1

您将同一个SqlParameter多次添加到同一个SqlCommand。问题是Parameters.Clear()从命令中删除参数，但参数仍然认为命令'拥有'它们。没有办法去除这个所有权。这是直观的，这是一个常见的错误:)

2种方法来解决这个问题：

1. 每个循环迭代

2. 创建新的SqlParameter对象或使用单一的SqlCommand（如你有什么）和拉sqlCmd.Parameters.Add到循环之外。例如

   SqlParameter sqlParaFaction_Faction_ID = new SqlParameter("@Faction_ID", SqlDbType.Int); 
       SqlParameter sqlParaFaction_ToFactionID = new SqlParameter("@ToFaction_ID", SqlDbType.Int); 
       SqlParameter sqlParaFaction_Standing = new SqlParameter("@Standing", SqlDbType.SmallInt); 
   
       using (SqlConnection sqlCnn = new SqlConnection(sqlCnnString)) 
       { 
        sqlCnn.Open(); 
        using (SqlTransaction sqlTrans = sqlCnn.BeginTransaction()) 
        { 
         using (SqlCommand sqlCmd = new SqlCommand()) 
         { 
          sqlCmd.Connection = sqlCnn; 
          string sqlCmdFactionStandings = "INSERT INTO FactionStandings (Faction_ID, ToFaction_ID, Standing) VALUES (@Faction_ID, @ToFaction_ID, @Standing)"; 
          sqlCmd.CommandText = sqlCmdFactionStandings; 
          sqlCmd.Transaction = sqlTrans; 
          sqlCmd.Parameters.Add(sqlParaFaction_Faction_ID); 
          sqlCmd.Parameters.Add(sqlParaFaction_ToFactionID); 
          sqlCmd.Parameters.Add(sqlParaFaction_Standing); 
   
          foreach (FactionStanding factionStanding in faction.FactionStandings) 
          { 
           // 
           // - Insert Faction Standing Table Data 
           // 
           sqlParaFaction_Faction_ID.Value = factionStanding.Faction_ID; 
           sqlParaFaction_ToFactionID.Value = factionStanding.ToFaction_ID; 
           sqlParaFaction_Standing.Value = factionStanding.DefaultStanding; 
   
           sqlCmd.ExecuteNonQuery(); 
          } 
   
          sqlTrans.Commit(); 
         } 
        } 
       } 
   }