在 DbContext 裡 全域性 記錄 SQL 日誌 ：

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    Database.Log = (query)=> Debug.Write(query);
}

獲取 IQueryable<T>/Commond 產生的SQL：

using (var context = new BlogContext()) 
{ 
    context.Database.Log = Console.Write; 
 
    var blog = context.Blogs.First(b => b.Title == "One Unicorn"); 
 
    blog.Posts.First().Title = "Green Eggs and Ham"; 
 
    blog.Posts.Add(new Post { Title = "I do not like them!" }); 
 
    context.SaveChangesAsync().Wait(); 
}
 

WebConfig中配置記錄全域性ef產生的SQL 日誌：

<interceptors> 
  <interceptor type="System.Data.Entity.Infrastructure.Interception.DatabaseLogger, EntityFramework"> 
    <parameters> 
      <parameter value="C:\Temp\LogOutput.txt"/> 
    </parameters> 
  </interceptor> 
</interceptors>
 

參考：

配置DbConfigration公約，不僅可以記錄語句還可以 記錄 執行效率

    //配置公約
    public class EFConfiguration : DbConfiguration
    {
        public EFConfiguration()
        {
            //AddInterceptor(new StringTrimmerInterceptor());
            ////或者註冊在Global.asax中的Application_Start 
            //DbInterception.Add(new EFIntercepterLogging());
        }
    }

    #region 使 EntityFrameWork 自動 去除字串 末尾 空格

    /// <summary>
    /// 設定 SQL 條件 "123 "與"123"比對的問題
    /// 使 EntityFrameWork 自動 去除字串 末尾 空格
    /// SQL 預設去除 最末尾的空格 "123 " 等價於 "123"
    /// </summary>
    public class StringTrimmerInterceptor : IDbCommandTreeInterceptor
    {
        public void TreeCreated(DbCommandTreeInterceptionContext interceptionContext)
        {
            if (interceptionContext.OriginalResult.DataSpace == DataSpace.SSpace)
            {
                var queryCommand = interceptionContext.Result as DbQueryCommandTree;
                if (queryCommand != null)
                {
                    var newQuery = queryCommand.Query.Accept(new StringTrimmerQueryVisitor());
                    interceptionContext.Result = new DbQueryCommandTree(
                        queryCommand.MetadataWorkspace,
                        queryCommand.DataSpace,
                        newQuery);
                }
            }
        }

        private class StringTrimmerQueryVisitor : DefaultExpressionVisitor
        {
            private static readonly string[] _typesToTrim = { "nvarchar", "varchar", "char", "nchar" };

            public override DbExpression Visit(DbNewInstanceExpression expression)
            {
                var arguments = expression.Arguments.Select(a =>
                {
                    var propertyArg = a as DbPropertyExpression;
                    if (propertyArg != null && _typesToTrim.Contains(propertyArg.Property.TypeUsage.EdmType.Name))
                    {
                        return EdmFunctions.Trim(a);
                    }

                    return a;
                });

                return DbExpressionBuilder.New(expression.ResultType, arguments);
            }
        }
    }

    #endregion

    #region 記錄 EntityFrameWork 生成的SQL 以及 效能

    /// <summary>
    /// 記錄 EntityFrameWork 生成的SQL 以及 效能
    /// 使用EntityFramework6.1的DbCommandInterceptor攔截生成的SQL語句
    /// </summary>
    public class EFIntercepterLogging : DbCommandInterceptor
    {
        private readonly Stopwatch _stopwatch = new Stopwatch();

        public override void ScalarExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
        {
            base.ScalarExecuting(command, interceptionContext);
            _stopwatch.Restart();
        }

        public override void ScalarExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
        {
            _stopwatch.Stop();
            if (interceptionContext.Exception != null)
            {
                Trace.TraceError("Exception:{1} \r\n --> Error executing command: {0}", command.CommandText, interceptionContext.Exception.ToString());
            }
            else
            {
                Trace.TraceInformation("\r\n執行時間:{0} 毫秒\r\n-->ScalarExecuted.Command:{1}\r\n", _stopwatch.ElapsedMilliseconds, command.CommandText);
            }
            base.ScalarExecuted(command, interceptionContext);
        }

        public override void NonQueryExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
        {
            base.NonQueryExecuting(command, interceptionContext);
            _stopwatch.Restart();
        }

        public override void NonQueryExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
        {
            _stopwatch.Stop();
            if (interceptionContext.Exception != null)
            {
                Trace.TraceError("Exception:{1} \r\n --> Error executing command:\r\n {0}", command.CommandText, interceptionContext.Exception.ToString());
            }
            else
            {
                Trace.TraceInformation("\r\n執行時間:{0} 毫秒\r\n-->NonQueryExecuted.Command:\r\n{1}", _stopwatch.ElapsedMilliseconds, command.CommandText);
            }
            base.NonQueryExecuted(command, interceptionContext);
        }

        public override void ReaderExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<System.Data.Common.DbDataReader> interceptionContext)
        {
            base.ReaderExecuting(command, interceptionContext);
            _stopwatch.Restart();
        }

        public override void ReaderExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContext<System.Data.Common.DbDataReader> interceptionContext)
        {
            _stopwatch.Stop();
            if (interceptionContext.Exception != null)
            {
                Trace.TraceError("Exception:{1} \r\n --> Error executing command:\r\n {0}", command.CommandText, interceptionContext.Exception.ToString());
            }
            else
            {
                Trace.TraceInformation("\r\n執行時間:{0} 毫秒 \r\n -->ReaderExecuted.Command:\r\n{1}", _stopwatch.ElapsedMilliseconds, command.CommandText);
            }
            base.ReaderExecuted(command, interceptionContext);
        }
    }

    #endregion