Default values for AdoNetAppender parameter - log4net

Question

I am using log4net with AdoNetAppender. It logs all log info into a table. This table actually has 2 Integer columns (can be null).
Here is the relevant part of my log4net config:
<commandText value="INSERT INTO ActivityLog ([Date],[Thread],[Level],[Logger],[Message],[DealID])
VALUES (#log_date,#thread,#log_level,#logger,#message,#DealID)" />
//other parameters hten DealID
<parameter>
<parameterName value="#DealID" />
<dbType value="Int32" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%property{DealID}" />
</layout>
</parameter>
What I found out was if I don't explicitly set using something like log4net.ThreadContext.Properties["DealID"] = DealID; it throws me an exception:
System.FormatException occurred
Message="Failed to convert parameter value from a String to a Int32."
Source="System.Data"
StackTrace:
at System.Data.SqlClient.SqlParameter.CoerceValue(Object value, MetaType destinationType)
InnerException: System.FormatException
Message="Input string was not in a correct format."
Source="mscorlib"
StackTrace:
at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info)
at System.String.System.IConvertible.ToInt32(IFormatProvider provider)
at System.Convert.ChangeType(Object value, Type conversionType, IFormatProvider provider)
at System.Data.SqlClient.SqlParameter.CoerceValue(Object value, MetaType destinationType)
InnerException:
I would have to set it like:
log4net.ThreadContext.Properties["DealID"] = 0;
Is there anyway that I can set a default parameter value in my log4net config for this Int32 field so that I don't need to set it explicitly to 0 if no value is supplied? And it makes me wonder why it does not happen to fields which are set as varchar (though no value is supplied to them).

Answer 1

Change your appender:
<parameter>
<parameterName value="#DealID" />
<dbType value="Int32" />
<layout type="log4net.Layout.RawPropertyLayout"> <!-- notice this -->
<key value="DealID" /> <!-- and notice this instead of the pattern layout -->
</layout>
</parameter>
And to give credit, I found it from this thread. (And a bunch of other searching trying to do the same thing.