Export (0) Print
Expand All

DefaultTraceListener Class

Provides the default output methods and behavior for tracing.

System.Object
  System.MarshalByRefObject
    System.Diagnostics.TraceListener
      System.Diagnostics.DefaultTraceListener

Namespace:  System.Diagnostics
Assembly:  System (in System.dll)

[HostProtectionAttribute(SecurityAction.LinkDemand, Synchronization = true)]
public class DefaultTraceListener : TraceListener

The DefaultTraceListener type exposes the following members.

  NameDescription
Public methodSupported by the XNA FrameworkDefaultTraceListenerInitializes a new instance of the DefaultTraceListener class with "Default" as its Name property value.
Top

  NameDescription
Public propertyAssertUiEnabledGets or sets a value indicating whether the application is running in user-interface mode.
Public propertyAttributesGets the custom trace listener attributes defined in the application configuration file. (Inherited from TraceListener.)
Public propertyFilterGets and sets the trace filter for the trace listener. (Inherited from TraceListener.)
Public propertySupported by the XNA FrameworkIndentLevelGets or sets the indent level. (Inherited from TraceListener.)
Public propertySupported by the XNA FrameworkIndentSizeGets or sets the number of spaces in an indent. (Inherited from TraceListener.)
Public propertyIsThreadSafeGets a value indicating whether the trace listener is thread safe. (Inherited from TraceListener.)
Public propertyLogFileNameGets or sets the name of a log file to write trace or debug messages to.
Public propertySupported by the XNA FrameworkNameGets or sets a name for this TraceListener. (Inherited from TraceListener.)
Protected propertySupported by the XNA FrameworkNeedIndentGets or sets a value indicating whether to indent the output. (Inherited from TraceListener.)
Public propertyTraceOutputOptionsGets or sets the trace output options. (Inherited from TraceListener.)
Top

  NameDescription
Public methodSupported by the XNA FrameworkCloseWhen overridden in a derived class, closes the output stream so it no longer receives tracing or debugging output. (Inherited from TraceListener.)
Public methodCreateObjRefCreates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.)
Public methodSupported by the XNA FrameworkDispose()Releases all resources used by the TraceListener. (Inherited from TraceListener.)
Protected methodSupported by the XNA FrameworkDispose(Boolean)Releases the unmanaged resources used by the TraceListener and optionally releases the managed resources. (Inherited from TraceListener.)
Public methodSupported by the XNA FrameworkEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Public methodSupported by the XNA FrameworkFail(String)Emits or displays a message and a stack trace for an assertion that always fails. (Overrides TraceListener.Fail(String).)
Public methodSupported by the XNA FrameworkFail(String, String)Emits or displays detailed messages and a stack trace for an assertion that always fails. (Overrides TraceListener.Fail(String, String).)
Protected methodSupported by the XNA FrameworkFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by the XNA FrameworkFlushWhen overridden in a derived class, flushes the output buffer. (Inherited from TraceListener.)
Public methodSupported by the XNA FrameworkGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetLifetimeServiceRetrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
Protected methodGetSupportedAttributesGets the custom attributes supported by the trace listener. (Inherited from TraceListener.)
Public methodSupported by the XNA FrameworkGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodInitializeLifetimeServiceObtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
Protected methodSupported by the XNA FrameworkMemberwiseClone()Creates a shallow copy of the current Object. (Inherited from Object.)
Protected methodMemberwiseClone(Boolean)Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject.)
Public methodSupported by the XNA FrameworkToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodTraceData(TraceEventCache, String, TraceEventType, Int32, Object)Writes trace information, a data object and event information to the listener specific output. (Inherited from TraceListener.)
Public methodTraceData(TraceEventCache, String, TraceEventType, Int32, Object[])Writes trace information, an array of data objects and event information to the listener specific output. (Inherited from TraceListener.)
Public methodTraceEvent(TraceEventCache, String, TraceEventType, Int32)Writes trace and event information to the listener specific output. (Inherited from TraceListener.)
Public methodTraceEvent(TraceEventCache, String, TraceEventType, Int32, String)Writes trace information, a message, and event information to the listener specific output. (Inherited from TraceListener.)
Public methodTraceEvent(TraceEventCache, String, TraceEventType, Int32, String, Object[])Writes trace information, a formatted array of objects and event information to the listener specific output. (Inherited from TraceListener.)
Public methodTraceTransferWrites trace information, a message, a related activity identity and event information to the listener specific output. (Inherited from TraceListener.)
Public methodSupported by the XNA FrameworkWrite(Object)Writes the value of the object's ToString method to the listener you create when you implement the TraceListener class. (Inherited from TraceListener.)
Public methodSupported by the XNA FrameworkWrite(String)Writes the output to the OutputDebugString function and to the Debugger.Log method. (Overrides TraceListener.Write(String).)
Public methodSupported by the XNA FrameworkWrite(Object, String)Writes a category name and the value of the object's ToString method to the listener you create when you implement the TraceListener class. (Inherited from TraceListener.)
Public methodSupported by the XNA FrameworkWrite(String, String)Writes a category name and a message to the listener you create when you implement the TraceListener class. (Inherited from TraceListener.)
Protected methodSupported by the XNA FrameworkWriteIndentWrites the indent to the listener you create when you implement this class, and resets the NeedIndent property to false. (Inherited from TraceListener.)
Public methodSupported by the XNA FrameworkWriteLine(Object)Writes the value of the object's ToString method to the listener you create when you implement the TraceListener class, followed by a line terminator. (Inherited from TraceListener.)
Public methodSupported by the XNA FrameworkWriteLine(String)Writes the output to the OutputDebugString function and to the Debugger.Log method, followed by a carriage return and line feed (\r\n). (Overrides TraceListener.WriteLine(String).)
Public methodSupported by the XNA FrameworkWriteLine(Object, String)Writes a category name and the value of the object's ToString method to the listener you create when you implement the TraceListener class, followed by a line terminator. (Inherited from TraceListener.)
Public methodSupported by the XNA FrameworkWriteLine(String, String)Writes a category name and a message to the listener you create when you implement the TraceListener class, followed by a line terminator. (Inherited from TraceListener.)
Top

An instance of this class is automatically added to the Debug.Listeners and Trace.Listeners collections. Explicitly adding a second DefaultTraceListener causes duplicate messages in the debugger output window and duplicate message boxes for asserts.

By default, the Write and WriteLine methods emit the message to the Win32 OutputDebugString function and to the Debugger.Log method. For information about the OutputDebugString function, see the Platform SDK or MSDN.

The Fail method, by default, displays a message box when the application is running in a user interface mode; it also emits the message using WriteLine.

NoteNote

The display of the message box for Assert and Fail method calls depends on the presence of the DefaultTraceListener. If the DefaultTraceListener is not in the Listeners collection, the message box is not displayed. The DefaultTraceListener can be removed by the <clear> element, by the <remove> element, or by calling the Clear method on the Listeners property (System.Diagnostics.Trace.Listeners.Clear()).

You must enable tracing or debugging to use a trace listener. The following syntax is compiler specific. If you use compilers other than C# or Visual Basic, refer to the documentation for your compiler.

  • To enable debugging in C#, add the /d:DEBUG flag to the compiler command line when you compile your code, or add #define DEBUG to the top of your file. In Visual Basic, add the /d:DEBUG=True flag to the compiler command line.

  • To enable tracing in C#, add the /d:TRACE flag to the compiler command line when you compile your code, or add #define TRACE to the top of your file. In Visual Basic, add the /d:TRACE=True flag to the compiler command line.

To add a trace listener, edit the configuration file that corresponds to the name of your application. Within this file, you can add a listener, set its type and set its parameters, remove a listener, or clear all the listeners previously set by the application. The configuration file should be formatted similar to the following example:

<configuration>
<system.diagnostics>
  <trace autoflush="false" indentsize="4">
    <listeners>
      <remove name="Default" />
      <add name="myListener"  type="System.Diagnostics.TextWriterTraceListener"    initializeData="c:\myListener.log" />
    </listeners>
  </trace>
</system.diagnostics>
</configuration>
NoteNote

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: Synchronization. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

The following code example calculates binomial coefficients, which are values used in probability and statistics. This example uses a DefaultTraceListener to trace results and log errors. It creates a new DefaultTraceListener, adds it to the Trace.Listeners collection, and sets the LogFileName property to the log file specified in the command-line arguments.

If an error is detected while processing the input parameter, or if the CalcBinomial function throws an exception, the Fail method logs and displays an error message. If the AssertUiEnabled property is false, the error message is also written to the console. When the result is calculated successfully, the Write(String) and WriteLine(String) methods write the results to the log file.

The Fail, Write, and WriteLine methods cause trace information to be written only to the DefaultTraceListener. To write trace information to all listeners in the Trace.Listeners collection, use the Fail, Write, and WriteLine methods of the Trace class.

using System;
using System.Diagnostics;
using Microsoft.VisualBasic;

class Binomial
{

    // args(0) is the number of possibilities for binomial coefficients. 
    // args(1) is the file specification for the trace log file. 
    public static void Main(string[] args)
    {

        decimal possibilities;
        decimal iter;

        // Remove the original default trace listener.
        Trace.Listeners.RemoveAt(0);

        // Create and add a new default trace listener.
        DefaultTraceListener defaultListener;
        defaultListener = new DefaultTraceListener();
        Trace.Listeners.Add(defaultListener);

        // Assign the log file specification from the command line, if entered. 
        if (args.Length>=2)
        {
            defaultListener.LogFileName = args[1];
        }

        // Validate the number of possibilities argument. 
        if (args.Length>=1)

            // Verify that the argument is a number within the correct range.
        {
            try
            {
                const decimal MAX_POSSIBILITIES = 99;
                possibilities = Decimal.Parse(args[0]);
                if (possibilities<0||possibilities>MAX_POSSIBILITIES)
                {
                    throw new Exception(String.Format("The number of possibilities must " +
                        "be in the range 0..{0}.", MAX_POSSIBILITIES));
                }
            }
            catch(Exception ex)
            {
                string failMessage = String.Format("\"{0}\" " +
                    "is not a valid number of possibilities.", args[0]);
                defaultListener.Fail(failMessage, ex.Message);
                if (!defaultListener.AssertUiEnabled)
                {
                    Console.WriteLine(failMessage+ "\n" +ex.Message);
                }
                return;
            }
        }
        else
        {
            // Report that the required argument is not present. 
            const string ENTER_PARAM = "Enter the number of " +
                      "possibilities as a command line argument.";
            defaultListener.Fail(ENTER_PARAM);
            if (!defaultListener.AssertUiEnabled)
            {
                Console.WriteLine(ENTER_PARAM);
            }
            return;
        }

        for(iter=0; iter<=possibilities; iter++)
        {
            decimal result;
            string binomial;

            // Compute the next binomial coefficient and handle all exceptions. 
            try
            {
                result = CalcBinomial(possibilities, iter);
            }
            catch(Exception ex)
            {
                string failMessage = String.Format("An exception was raised when " +
                    "calculating Binomial( {0}, {1} ).", possibilities, iter);
                defaultListener.Fail(failMessage, ex.Message);
                if (!defaultListener.AssertUiEnabled)
                {
                    Console.WriteLine(failMessage+ "\n" +ex.Message);
                }
                return;
            }

            // Format the trace and console output.
            binomial = String.Format("Binomial( {0}, {1} ) = ", possibilities, iter);
            defaultListener.Write(binomial);
            defaultListener.WriteLine(result.ToString());
            Console.WriteLine("{0} {1}", binomial, result);
        }
    }

    public static decimal CalcBinomial(decimal possibilities, decimal outcomes)
    {

        // Calculate a binomial coefficient, and minimize the chance of overflow. 
        decimal result = 1;
        decimal iter;
        for(iter=1; iter<=possibilities-outcomes; iter++)
        {
            result *= outcomes+iter;
            result /= iter;
        }
        return result;
    }
}

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

This class is thread safe.

Show:
© 2014 Microsoft