The MySqlParameterCollection only accepts non-null MySqlParameter type objects

mysql连接器 不支持将null参数传递给连接，所以在加入以前必须得判断是否为null，类似sqlhelper应该修改一下：

 

private static void PrepareCommand(MySqlCommand cmd, MySqlConnection conn, MySqlTransaction trans, CommandType cmdType, string cmdText, MySqlParameter[] cmdParms)
        {

            if (conn.State != ConnectionState.Open)
                conn.Open();

            cmd.Connection = conn;
            cmd.CommandText = cmdText;

            if (trans != null)
                cmd.Transaction = trans;

            cmd.CommandType = cmdType;

            if (cmdParms != null)
            {
                foreach (MySqlParameter parm in cmdParms)
                {
                    if (parm != null)
                        cmd.Parameters.Add(parm);
                }

            }
        }