Chapter 16: Debugging

Tracing

There are two types of tracing that you can do with the System.Diagnostics namespace. You can use the Trace class to place Trace statements in both the retail and debug builds, without requiring a recompilation. The Debug class exists only in the debug build of an application, but the overall goal and results are the same as using the Trace class.

Tip

A healthy dose of tracing and debug logging in your application will save you many hours of support work and debugging. The Microsoft Exchange team included extended amounts of tracing in the transport components of Exchange 2000. This saved thousands of hours in troubleshooting and debugging.

By default, tracing information is sent to the debugger, but you have the following choices for listeners: debugger ( DefaultTraceListener ), file or console ( TextWriterTraceListener ), or event log ( EventLogTraceListener ).

You can enable tracing using one of these methods:

Define the compilation constant TRACE and set it to true.
Use the BooleanSwitch class.

Use the TraceSwitch class and configuration file. This provides a multilevel switch to control tracing and debug output without recompiling your code.

TraceSwitch MySwitch = new TraceSwitch(
     "MySwitch", MySwitch.Level=TraceLevel.Info);


<system.diagnostics>
         <switches>
                <add name="My Switch" value =0
          </switches>
</system.diagnostics>

The following examples demonstrate tracing methods.

Note

When tracing to a file, event log, the debugger, or console, you can use the Debug class instead of the Trace class if you want to do the tracing only in debug mode.

Code Example: Tracing to a File

using System;
using System.IO;
using System.Diagnostics;

namespace Client.Chapter_16___Debugging
{
          class TracingToAFile
          {
                [STAThread]
                static void Main(string[] args)
                {
                       FileStream Log =
                          new FileStream("Log.txt", FileMode.OpenOrCreate);
                       Trace.Listeners.Add(new TextWriterTraceListener(Log));
                       Trace.WriteLine("My Trace String To Log File");
                       Trace.Flush();
                       Log.Close();
               }
          }
}

Code Example: Tracing to the Event Log


using System;
using System.IO;
using System.Diagnostics;

namespace Client.Chapter_16___Debugging
{
          class TracingToEventLog
          {
                [STAThread]
                static void Main(string[] args)
                {
                      //You can change the listener with the following code
                       EventLogTraceListener EventListener =
                          new EventLogTraceListener("MyApp");
                       Trace.Listeners.Add(EventListener);
                       Trace.WriteLine("My Trace String To Console");
                }
          }
}

Code Example: Tracing to the Debugger


using System;
using System.IO;
using System.Diagnostics;

namespace Client.Chapter_16___Debugging
{
          class TracingToDebugger
          {
                [STAThread]
                static void Main(string[] args)
                {
                      Trace.WriteLine("My Trace String");
                      Trace.Flush();
                }
          }
}

Code Example: Tracing to the Console

using System;
using System.IO;
using System.Diagnostics;

namespace Client.Chapter_16___Debugging
{
          class Class1
          {
                [STAThread]
                static void Main(string[] args)
                {
                       Trace.Listeners.Add(
                          new TextWriterTraceListener(Console.Out));
                       Trace.WriteLine("My Trace to the console");
                }
          }
}

Code Example: Using BooleanSwitch


using System;
using System.IO;
using System.Diagnostics;

namespace Client.Chapter_16___Debugging
{
          class UsingBooleanSwitch
          {
                 static BooleanSwitch MySwitch =
                    new BooleanSwitch("MyData", "MyModule");
                 [STAThread]
                 static void Main(string[] args)
                 {
                        MySwitch.Enabled = true;
                        if (MySwitch.Enabled)
                               Console.WriteLine("Error happened!");
                 }
          }
}

Code Example: Using TraceSwitch and Config Files


using System;
using System.Diagnostics;

namespace Client.Chapter_16___Debugging
{
          class TracingExample
          {
                static void Main(string[] args)
                {
                       TraceSwitch General =
                           new TraceSwitch("General", "Application Switch");
                       Trace.WriteLineIf(General.TraceError,
                           "General - Error Tracing Enabled");
                       Trace.WriteLineIf(General.TraceWarning,
                           "General - Warning Tracing Enabled");
                       Trace.WriteLineIf(General.TraceInfo,
                           "General - Info Tracing Enabled");
                       Trace.WriteLineIf(General.TraceVerbose,
                           "General - Verbose Tracing Enabled");
                       TraceSwitch MyComponent =
                           new TraceSwitch("MyComponent", "Application Switch");
                       Trace.WriteLineIf(MyComponent.TraceError,
                           "MyComponent - Error Tracing Enabled");
                       Trace.WriteLineIf(MyComponent.TraceWarning,
                           "MyComponent - Warning Tracing Enabled");
                       Trace.WriteLineIf(MyComponent.TraceInfo,
                           "MyComponent - Info Tracing Enabled");
                       Trace.WriteLineIf(MyComponent.TraceVerbose,
                           "MyComponent - Verbose Tracing Enabled");
                }
          }
}

The configuration file settings are as follows:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
        <system.diagnostics>
            <switches>
            <add name="General" value="1" />
            <add name="MyComponent" value="3" />
        </switches>
   </system.diagnostics>
</configuration>

The values settings in the configuration file are as follows:

Off	0
Error	1
Warnings & Error	2
Info, Warning & Error	3
Verbose	4