// Specify /d:TRACE when compiling.
static void Main()
Trace.AutoFlush = true;
' Specify /d:TRACE=True when compiling.
Shared Sub Main()
Trace.AutoFlush = True
End Sub 'Main
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, and WriteLineIf.
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.
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.
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.
To set the AutoFlush and IndentSize for Trace, you can edit the configuration file that corresponds to the name of your application. The configuration file should be formatted like the following example:
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.
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. For information about how to disable this behavior, see the Visual Studio documentation.
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.