Trace Class

Definition

Namespace:

System.Diagnostics

Assembly:

System.Diagnostics.TraceSource.dll

Source:

Trace.cs

Provides a set of methods and properties that help you trace the execution of your code. This class cannot be inherited.

public ref class Trace sealed

public sealed class Trace

type Trace = class

Public NotInheritable Class Trace

Inheritance

Object

Trace

Examples

The following example uses Trace to indicate the beginning and the end of a program's execution. The example also uses the Trace.Indent and Trace.Unindent methods to distinguish the tracing output. For a more complete example of the use of Trace, see How to: Add Trace Statements to Application Code.

// Specify /DTRACE when compiling.

#using <System.dll>
using namespace System;
using namespace System::Diagnostics;

int main()
{
   #if defined(TRACE)
   Trace::Listeners->Add( gcnew TextWriterTraceListener( Console::Out ) );
   Trace::AutoFlush = true;
   Trace::Indent();
   Trace::WriteLine( "Entering Main" );
   #endif
   Console::WriteLine( "Hello World." );
   #if defined(TRACE)
   Trace::WriteLine( "Exiting Main" );
   Trace::Unindent();
   #endif
   return 0;
}

// Specify /d:TRACE when compiling.

using System;
using System.Diagnostics;

class Test
{
    static void Main()
    {
       Trace.Listeners.Add(new TextWriterTraceListener(Console.Out));
       Trace.AutoFlush = true;
       Trace.Indent();
       Trace.WriteLine("Entering Main");
       Console.WriteLine("Hello World.");
       Trace.WriteLine("Exiting Main");
       Trace.Unindent();
    }
}

' Specify /d:TRACE=True when compiling.

Imports System.Diagnostics

Class Test
    
    Shared Sub Main()
    
        Trace.Listeners.Add(New TextWriterTraceListener(Console.Out))
        Trace.AutoFlush = True
        Trace.Indent()
        Trace.WriteLine("Entering Main")
        Console.WriteLine("Hello World.")
        Trace.WriteLine("Exiting Main")
        Trace.Unindent()
        
    End Sub

End Class

Remarks

You can use the properties and methods in the Trace class to instrument release builds. Instrumentation allows you to monitor the health of your application running in real-life settings. Tracing helps you isolate problems and fix them without disturbing a running system.

This class provides methods to display an Assert dialog box, and to emit an assertion that will always Fail. This class provides write methods in the following variations:

• Write
• WriteLine
• WriteIf
• WriteLineIf

The BooleanSwitch and TraceSwitch classes provide means to dynamically control the tracing output. In .NET Framework apps, you can modify the values of these switches without recompiling your application. For information on using the configuration file to set a switch in a .NET Framework app, see the Switch class and How to: Create, Initialize, and Configure Trace Switches.

You can customize the tracing output's target by adding TraceListener instances to or removing instances from the Listeners collection. The Listeners collection is shared by both the Debug and the Trace classes; adding a trace listener to either class adds the listener to both. By default, trace output is emitted using the DefaultTraceListener class.

Note

Adding a trace listener to the Listeners collection can cause an exception to be thrown while tracing, if a resource used by the trace listener is not available. The conditions and the exception thrown depend on the trace listener and cannot be enumerated in this topic. It may be useful to place calls to the Trace methods in try/catch blocks to detect and handle any exceptions from trace listeners.

Note

If you add trace listeners to partially trusted code, you will get a SecurityException exception, because adding trace listeners requires UnmanagedCode permission. To trace partially trusted code that is running in a sandbox in Visual Studio, do not add trace listeners. Instead, view the Trace and Debug messages in the Output window.

The Trace class provides properties to get or set the level of Indent and the IndentSize, and whether to AutoFlush after each write.

In .NET Framework apps, you can set the AutoFlush and IndentSize for Trace by editing the configuration file that corresponds to the name of your application. The configuration file should be formatted like the following example:

<configuration>  
  <system.diagnostics>  
    <trace autoflush="false" indentsize="3" />  
  </system.diagnostics>  
</configuration>  

The ConditionalAttribute attribute is applied to the methods of Trace. Compilers that support ConditionalAttribute ignore calls to these methods unless TRACE is defined as a conditional compilation symbol. Refer to a compiler's documentation to determine whether ConditionalAttribute is supported and the syntax for defining a conditional compilation symbol.

Note

In Visual Studio projects, by default, the DEBUG conditional compilation symbol is defined for debug builds, and the TRACE symbol is defined for both debug and release builds.

To define the TRACE conditional compilation symbol in C#, add the /d:TRACE option to the compiler command line when you compile your code using a command line, or add #define TRACE to the top of your file. In Visual Basic, add the /d:TRACE=True option to the compiler command line or add #Const TRACE=True to the file.

ConditionalAttribute is not supported by the C++ compiler. To provide equivalent functionality, you must enclose calls to the methods of Trace in an #if defined(TRACE) ... #endif block, and add the /DTRACE option to the compiler command line or add #define TRACE to the file.

Properties

AutoFlush	Gets or sets whether Flush() should be called on the Listeners after every write.
CorrelationManager	Gets the correlation manager for the thread for this trace.
IndentLevel	Gets or sets the indent level.
IndentSize	Gets or sets the number of spaces in an indent.
Listeners	Gets the collection of listeners that is monitoring the trace output.
UseGlobalLock	Gets or sets a value indicating whether the global lock should be used.

Methods

Assert(Boolean)	Checks for a condition; if the condition is false, displays a message box that shows the call stack.
Assert(Boolean, String)	Checks for a condition; if the condition is false, outputs a specified message and displays a message box that shows the call stack.
Assert(Boolean, String, String)	Checks for a condition; if the condition is false, outputs two specified messages and displays a message box that shows the call stack.
Close()	Flushes the output buffer, and then closes the Listeners.
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
Fail(String)	Emits the specified error message.
Fail(String, String)	Emits an error message, and a detailed error message.
Flush()	Flushes the output buffer, and causes buffered data to be written to the Listeners.
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
Indent()	Increases the current IndentLevel by one.
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
Refresh()	Refreshes the trace configuration data.
ToString()	Returns a string that represents the current object. (Inherited from Object)
TraceError(String)	Writes an error message to the trace listeners in the Listeners collection using the specified message.
TraceError(String, Object[])	Writes an error message to the trace listeners in the Listeners collection using the specified array of objects and formatting information.
TraceInformation(String)	Writes an informational message to the trace listeners in the Listeners collection using the specified message.
TraceInformation(String, Object[])	Writes an informational message to the trace listeners in the Listeners collection using the specified array of objects and formatting information.
TraceWarning(String)	Writes a warning message to the trace listeners in the Listeners collection using the specified message.
TraceWarning(String, Object[])	Writes a warning message to the trace listeners in the Listeners collection using the specified array of objects and formatting information.
Unindent()	Decreases the current IndentLevel by one.
Write(Object)	Writes the value of the object's ToString() method to the trace listeners in the Listeners collection.
Write(Object, String)	Writes a category name and the value of the object's ToString() method to the trace listeners in the Listeners collection.
Write(String)	Writes a message to the trace listeners in the Listeners collection.
Write(String, String)	Writes a category name and a message to the trace listeners in the Listeners collection.
WriteIf(Boolean, Object)	Writes the value of the object's ToString() method to the trace listeners in the Listeners collection if a condition is true.
WriteIf(Boolean, Object, String)	Writes a category name and the value of the object's ToString() method to the trace listeners in the Listeners collection if a condition is true.
WriteIf(Boolean, String)	Writes a message to the trace listeners in the Listeners collection if a condition is true.
WriteIf(Boolean, String, String)	Writes a category name and message to the trace listeners in the Listeners collection if a condition is true.
WriteLine(Object)	Writes the value of the object's ToString() method to the trace listeners in the Listeners collection.
WriteLine(Object, String)	Writes a category name and the value of the object's ToString() method to the trace listeners in the Listeners collection.
WriteLine(String)	Writes a message to the trace listeners in the Listeners collection.
WriteLine(String, String)	Writes a category name and message to the trace listeners in the Listeners collection.
WriteLineIf(Boolean, Object)	Writes the value of the object's ToString() method to the trace listeners in the Listeners collection if a condition is true.
WriteLineIf(Boolean, Object, String)	Writes a category name and the value of the object's ToString() method to the trace listeners in the Listeners collection if a condition is true.
WriteLineIf(Boolean, String)	Writes a message to the trace listeners in the Listeners collection if a condition is true.
WriteLineIf(Boolean, String, String)	Writes a category name and message to the trace listeners in the Listeners collection if a condition is true.

Events

Refreshing

Occurs when a TraceSource needs to be refreshed from configuration.

Thread Safety

This type is thread safe.

See also

• Debug
• Switch
• BooleanSwitch
• TraceSwitch
• TraceListener
• DefaultTraceListener
• EventLogTraceListener
• TraceListenerCollection
• ConditionalAttribute