最近做了箇中等的專案，資料不會很多，開發時間比較緊迫，所以用了EF的框架。

在使用過程中，發現有時候執行的結果不如預期，想看看執行的sql語句為何，遍查詢資料，在網上找到了相關輔助類，拿來使用，部署到生產環境。

程式碼如下：

    public class EFIntercepterLogging : DbCommandInterceptor
    {

        ILog log = LogManager.GetLogger("InfoAppender");
        private readonly Stopwatch _stopwatch = new Stopwatch();
        
 
public override void ScalarExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
        {
            SaveCmdSql(command);
            base.ScalarExecuting(command, interceptionContext);
            _stopwatch.Restart();
        }
        public
 
 override void ScalarExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
        {
            _stopwatch.Stop();
            SaveCmdSql(command);
            if (interceptionContext.Exception != null)
            {
                Trace.TraceError(
 
"Exception:{1} rn --> Error executing command: {0}", command.CommandText, interceptionContext.Exception.ToString());
            }
            else
            {
                Trace.TraceInformation("rn執行時間:{0} 毫秒rn-->ScalarExecuted.Command:{1}rn", _stopwatch.ElapsedMilliseconds, command.CommandText);
            }
            base.ScalarExecuted(command, interceptionContext);
        }
        public override void NonQueryExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
        {
            SaveCmdSql(command);
            base.NonQueryExecuting(command, interceptionContext);
            _stopwatch.Restart();
        }
        public override void NonQueryExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
        {
            _stopwatch.Stop();
            SaveCmdSql(command);
            if (interceptionContext.Exception != null)
            {
                Trace.TraceError("Exception:{1} rn --> Error executing command:rn {0}", command.CommandText, interceptionContext.Exception.ToString());
            }
            else
            {
                Trace.TraceInformation("rn執行時間:{0} 毫秒rn-->NonQueryExecuted.Command:rn{1}", _stopwatch.ElapsedMilliseconds, command.CommandText);
            }
            base.NonQueryExecuted(command, interceptionContext);
        }
        /// <summary>
        /// 讀取操作
        /// </summary>
        /// <param name="command"></param>
        /// <param name="interceptionContext"></param>
        public override void ReaderExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<System.Data.Common.DbDataReader> interceptionContext)
        {
            SaveCmdSql(command);
            base.ReaderExecuting(command, interceptionContext);
            _stopwatch.Restart();
        }
        public override void ReaderExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContext<System.Data.Common.DbDataReader> interceptionContext)
        {
            _stopwatch.Stop();
            SaveCmdSql(command);
            if (interceptionContext.Exception != null)
            {
                Trace.TraceError("Exception:{1} rn --> Error executing command:rn {0}", command.CommandText, interceptionContext.Exception.ToString());
            }
            else
            {
                Trace.TraceInformation("rn執行時間:{0} 毫秒 rn -->ReaderExecuted.Command:rn{1}", _stopwatch.ElapsedMilliseconds, command.CommandText);
            }
            base.ReaderExecuted(command, interceptionContext);
        }
        //儲存執行的sql語句
        public void SaveCmdSql(DbCommand command)
        {
            log.Info(command.CommandText);
        }

    }

程式碼比較容易理解，重點在 DbCommandInterceptor 這個類.

msdn 連結：https://docs.microsoft.com/zh-cn/dotnet/api/system.data.entity.infrastructure.interception.dbcommandinterceptor?view=entity-framework-6.2.0

需要Global.asax中全域性註冊該方法，才能使用

  DbInterception.Add(new EFIntercepterLogging());//註冊EF監控,寫日誌