DateTime format in log4net AdoNetAppender - log4net

Question

I'm using log4net and trying to pass a custom DateTime property to a database using the AdoNetAppender. I can pass in the DateTime value just fine, but the database value excludes the milliseconds. The final value is rounded to the nearest second.
I know there's the date{} formatting, but I cannot get that to work with a custom property. So, is it possible to format a custom DateTime property to include the milliseconds?
Here's my config:
<log4net>
<appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender">
<bufferSize value="0" />
<connectionType value="System.Data.SqlClient.SqlConnection, System.Data, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
<connectionString value="{MyConnectionString}" />
<commandText value="INSERT INTO MyTestLog ([Date],[Thread],[Level],[Logger],[Message],[Exception],[StartDate]) VALUES (#log_date, #thread, #log_level, #logger, #message, #exception, #start_date)" />
<parameter>
<parameterName value="#log_date" />
<dbType value="DateTime" />
<layout type="log4net.Layout.RawTimeStampLayout" />
</parameter>
<parameter>
<parameterName value="#thread" />
<dbType value="String" />
<size value="255" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%thread" />
</layout>
</parameter>
<parameter>
<parameterName value="#log_level" />
<dbType value="String" />
<size value="50" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%level" />
</layout>
</parameter>
<parameter>
<parameterName value="#logger" />
<dbType value="String" />
<size value="255" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%logger" />
</layout>
</parameter>
<parameter>
<parameterName value="#message" />
<dbType value="String" />
<size value="4000" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%message" />
</layout>
</parameter>
<parameter>
<parameterName value="#exception" />
<dbType value="String" />
<size value="2000" />
<layout type="log4net.Layout.ExceptionLayout" />
</parameter>
<parameter>
<parameterName value="#start_date"/>
<dbType value="DateTime" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%property{StartDate}" />
</layout>
</parameter>
</appender>
<root>
<level value="ALL" />
<appender-ref ref="AdoNetAppender" />
</root>
</log4net>
My logging code is:
ThreadContext.Properties["StartDate"] = DateTime.Now.AddMinutes(-10);
log.Info("Info message w/ StartTime property");
The resulting value is correct (10 minutes ago), but the value is rounded to the nearest second.
I can get it to work if I first reformat the DateTime to a String, like this:
ThreadContext.Properties["StartDate"] = DateTime.Now.AddMinutes(-10).ToString("yyyy-MM-ddTHH:mm:ss.fffzzz");
However, this seems less than optimal. Any ideas??

Answer 1

Option 1
Use log4net.Layout.RawPropertyLayout instead; e.g:
<parameter>
<parameterName value="#start_date"/>
<dbType value="DateTime" />
<layout type="log4net.Layout.RawPropertyLayout">
<key value="StartDate" />
</layout>
</parameter>
Option 2
Create this (it could be a struct if you prefer and might reduce heap allocations depending on how you use it):
public class Log4NetDateTime
{
private DateTime _value;
public Log4NetDateTime(DateTime value)
{
_value = value;
}
public override string ToString()
{
return _value.ToString("yyyy-MM-dd HH:mm:ss.fff");
}
}
Then add Log4NetDateTime values instead of DateTime values.
log4net.Layout.PatternLayout (via log4net.Util.PatternConverter) just calls ToString() on the object, and by default this does not include milliseconds.