Prøv:
<commandText value="StorProcName" />
<commandType value="StoredProcedure" />
<parameter>
<parameterName value="@log_date" />
<dbType value="DateTime" />
<layout type="log4net.Layout.RawTimeStampLayout" />
</parameter>
... all parameters ...
log4net online konfigurationseksempler side :