求助！log4net写入oracle问题

Question

我在C#.net下用log4net写入日志到oracle，可是写入的数据不对，请各位帮帮我看哪里出错了？
配置文件<?xml version="1.0" encoding="utf-8" ?>
  <configuration>
    <configSections>
      <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net" />
    </configSections>
    <log4net>
      
      <logger name="LogSystem">
        <level value="DEBUG" />
        <appender-ref ref="AdoNetAppender_Oracle" />
      </logger>
      
      <!--记录到数据库方式-->
      <appender name="AdoNetAppender_Oracle" type="log4net.Appender.AdoNetAppender">
        <connectionType value="System.Data.OracleClient.OracleConnection, System.Data.OracleClient, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
        <connectionString value="data source=orcl;User ID=yuan;Password=abc" />
        <commandText value="INSERT INTO LOG(DATETIME,THREAD,LOG_LEVEL,LOGGER,MESSAGE) VALUES (:log_date, :thread, :log_level, :logger, :log_message)" />
        <bufferSize value="128" />
        <parameter>
          <parameterName value=":log_date" />
          <dbType value="DateTime" />
          <layout type="log4net.Layout.RawTimeStampLayout" />
        </parameter>
        <parameter>
          <parameterName value=":thread" />
          <dbType value="String" />
          <size value="50" />
          <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%thread"/>
          </layout>
        </parameter>
        <parameter>
          <parameterName value=":log_level"/>
          <dbType value="String" />
          <size value="40" />
          <layout type="log4net.Layout.PatternLayout">
          <conversionPattern value="%level"/>
          </layout>
        </parameter>
        <parameter>
          <parameterName value=":logger"/>
          <dbType value="String" />
          <size value="100" />
          <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%logger" />
          </layout>
        </parameter>
        <parameter>
          <parameterName value=":log_message" />
          <dbType value="String" />
          <size value="200" />
          <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%message" />
          </layout>
        </parameter>
      </appender>      <!-- setup the root category, add the appenders and set the default level -->
      <root>        <level value="ALL"/>        <appender-ref ref="AdoNetAppender_Oracle" />
      </root>
      </log4net>
</configuration> 调用程序
配置了：[assembly: log4net.Config.DOMConfigurator(Watch = true)]namespace log4net
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private static log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
        private void button1_Click(object sender, EventArgs e)
        {
            log.Info("lalal");
            log.Debug("debug");
            log.Error("error");
            
        }
    }
oracle记录的数据都是这样的：
Thread：5916hread
Log_level：log4net.Form1.button1_Click(C:\Users\Administrator\Desktop\log4net\log4net\Form1.cs:22)evel
Message：***essage
查了好长时间不知道是怎么回事儿，请各位指点！！非常感谢！！