public DataContract DoSmthWithClass(DataContract dataContract) { EventLog tmpEventLog = new EventLog(); tmpEventLog.Source = "Test WCF"; tmpEventLog.WriteEntry(string.Format("ServiceContract.DoSmthWithClass({0}) before sleep", dataContract.StringField), EventLogEntryType.Information); Thread.Sleep(mSec); tmpEventLog.WriteEntry(string.Format("ServiceContract.DoSmthWithClass({0}) after sleep", dataContract.StringField), EventLogEntryType.Information); tmpEventLog.WriteEntry(string.Format("ServiceContract.DoSmthWithClass({0}) before BusinessLogic.DoSmthWithClass()", dataContract.StringField), EventLogEntryType.Information); DataContract result = (DataContract)_businessLogic.DoSmthWithClass(dataContract); tmpEventLog.WriteEntry(string.Format("ServiceContract.DoSmthWithClass({0}) after BusinessLogic.DoSmthWithClass()", dataContract.StringField), EventLogEntryType.Information); return(result); }