Logging: Create a wrapper around MS EntLib Logging

Create a LogManager static class in your framework.
Logger, LogEntry, ShouldLog are all provided by EntLib
LogCategory is an enum which can describe from which layer this log was generated.

public static class LogManager  
 {  
 public static void LogMessage(LogCategory category, LogPriority priority, string message)  
 {  
   string eventCategory = category.ToString();  
   LogEntry le = new LogEntry();  
   le.Priority = (int)priority;  
   le.Categories.Add(eventCategory);  
   if (Logger.ShouldLog(le))  
   {  
      le.TimeStamp = DateTime.Now;  
      le.Message = message;  
      le.ExtendedProperties.Add("Event Source:", eventCategory);  
      if (category == LogCategory.SystemErrorTrace || category == LogCategory.FatalErrorTrace)  
      {  
        le.Severity = System.Diagnostics.TraceEventType.Error;  
      }  
      try  
      {  
        Logger.Write(le);  
      }  
      catch (Exception)  
      {  
      }  
   }  
  }  
 }  

If you need to log an entity as XML:

public static void LogEntity(LogCategory category, LogPriority priority, object valueToLog, string logMessage)  
 {  
   string eventCategory = category.ToString();  
   LogEntry le = new LogEntry();  
   le.Priority = (int)priority;  
   le.Categories.Add(eventCategory);  
   if (Logger.ShouldLog(le))  
   {  
      using (StringWriter stringWriter = new StringWriter(CultureInfo.InvariantCulture))  
      {  
        if (valueToLog != null)  
        {  
           try  
           {  
             stringWriter.WriteLine(logMessage);  
             // Serailize the input object to stream  
             XmlSerializer xmlSerializer = new XmlSerializer(valueToLog.GetType());  
             xmlSerializer.Serialize(stringWriter, valueToLog);  
           }  
           catch (Exception ex)  
           {  
             stringWriter.WriteLine("Something wrong"+ex.Message);  
           }  
        }  
        else  
        {  
           stringWriter.WriteLine("Entity object = null");  
        }  
        try  
        {  
           le.TimeStamp = DateTime.Now;  
           le.ExtendedProperties.Add("Event Source:", eventCategory);  
           le.Message = stringWriter.ToString();  
           if (category == LogCategory.SystemErrorTrace || category == LogCategory.FatalErrorTrace)  
           {  
             le.Severity = System.Diagnostics.TraceEventType.Error;  
           }  
           Logger.Write(le);  
        }  
        catch (Exception)  
        {  
        }  
      }  
   }  
 }  

How Logging disabling works:
Below is snippet from web.config file:

<logFilters>  
 <add categoryFilterMode="AllowAllExceptDenied" type="Microsoft.Practices.EnterpriseLibrary.Logging.Filters.CategoryFilter, Microsoft.Practices.EnterpriseLibrary.Logging, Version=2.0.0.0, Culture=neutral, PublicKeyToken=7fa4cc4c62ff1809"  
 name="Category Filter">  
 <categoryFilters>  
  <!--<add name="SourceTrace" />  
  <add name="ManagerTrace" />  
  <add name="ProviderTrace" />  
  <add name="InformationTrace" />  
  <add name="ServiceTrace" />-->  
 </categoryFilters>  
 </add>  
 </logFilters>  
 <categorySources>  
 ..  
 </categorySources>  

Logging will be disabled only when a category filter is commented. tracingEnabled="false" does not work.