Thank you for this information.

What I try now is the following. Maybe somebody has suggestions for this
approach..

In the BaseEvent i check the EventSource.Parameters and filter events
depending on property values. This is done by doing a regular expression
check with RegEx.IsMatch(<property value>,<regular expression from eif
config>).

The entry in the EnterpriseInstrumentation.config could be (this checks
occurence of String1 OR String2 in the property MyProperty, if true the
event is send to the configured sinks):

<eventSource name="MySource" type="softwareElement"
internalExceptionHandler="report">
     <eventSourceParameter name="MyProperty" value="String1|String2" />
</eventSource>

If the Reg. Expr matches then PrepareForSerialization can return true.
Otherwise false.

Im doing the check with something like this (is not yet completed)

private Boolean IsEventFiltered(EventSource eventSource)
 {
  bool bIsFiltered = true;
  foreach(Object oKey in eventSource.Parameters.Keys)
  {
   bIsFiltered = IsPropertyFiltered(this.GetType(),
oKey.ToString(),eventSource.Parameters[oKey].ToString());
   if(!bIsFiltered) return false;
  }
  return bIsFiltered;
 }

 private Boolean IsPropertyFiltered(Type poType, string psPropertyName,
string psFilter)
 {
  try
  {
   string sPropertyValue = poType.InvokeMember(psPropertyName,
    BindingFlags.DeclaredOnly |
    BindingFlags.Public |
    BindingFlags.NonPublic |
    BindingFlags.Instance |
    BindingFlags.GetProperty,
    null, this, null).ToString();
   return
System.Text.RegularExpressions.Regex.IsMatch(sPropertyValue,psFilter);
  }
  catch
  {
   return true;
  }
 }

moi moi
Bernd