TraceListener Class
Provides the abstract base class for the listeners who monitor trace and debug output.
System.MarshalByRefObject
System.Diagnostics.TraceListener
Microsoft.VisualBasic.Logging.FileLogTraceListener
System.Diagnostics.DefaultTraceListener
System.Diagnostics.Eventing.EventProviderTraceListener
System.Diagnostics.EventLogTraceListener
System.Diagnostics.TextWriterTraceListener
System.Web.IisTraceListener
System.Web.WebPageTraceListener
Namespace: System.Diagnostics
Assembly: System (in System.dll)
The TraceListener type exposes the following members.
| Name | Description | |
|---|---|---|
  | TraceListener() | Initializes a new instance of the TraceListener class. |
| TraceListener(String) | Initializes a new instance of the TraceListener class using the specified name as the listener. |
| Name | Description | |
|---|---|---|
 | Attributes | Gets the custom trace listener attributes defined in the application configuration file. |
| Filter | Gets and sets the trace filter for the trace listener. |
| IndentLevel | Gets or sets the indent level. |
| IndentSize | Gets or sets the number of spaces in an indent. |
| IsThreadSafe | Gets a value indicating whether the trace listener is thread safe. |
| Name | Gets or sets a name for this TraceListener. |
 | NeedIndent | Gets or sets a value indicating whether to indent the output. |
| TraceOutputOptions | Gets or sets the trace output options. |
| Name | Description | |
|---|---|---|
 | Close | When overridden in a derived class, closes the output stream so it no longer receives tracing or debugging output. |
| CreateObjRef | Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.) |
| Dispose() | Releases all resources used by the TraceListener. |
| Dispose(Boolean) | Releases the unmanaged resources used by the TraceListener and optionally releases the managed resources. |
| Equals(Object) | Determines whether the specified object is equal to the current object. (Inherited from Object.) |
| Fail(String) | Emits an error message to the listener you create when you implement the TraceListener class. |
| Fail(String, String) | Emits an error message and a detailed error message to the listener you create when you implement the TraceListener class. |
| Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
| Flush | When overridden in a derived class, flushes the output buffer. |
| GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
| GetLifetimeService | Retrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.) |
| GetSupportedAttributes | Gets the custom attributes supported by the trace listener. |
| GetType | Gets the Type of the current instance. (Inherited from Object.) |
| InitializeLifetimeService | Obtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject.) |
| MemberwiseClone() | Creates a shallow copy of the current Object. (Inherited from Object.) |
| MemberwiseClone(Boolean) | Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject.) |
| ToString | Returns a string that represents the current object. (Inherited from Object.) |
| TraceData(TraceEventCache, String, TraceEventType, Int32, Object) | Writes trace information, a data object and event information to the listener specific output. |
| TraceData(TraceEventCache, String, TraceEventType, Int32, Object[]) | Writes trace information, an array of data objects and event information to the listener specific output. |
| TraceEvent(TraceEventCache, String, TraceEventType, Int32) | Writes trace and event information to the listener specific output. |
| TraceEvent(TraceEventCache, String, TraceEventType, Int32, String) | Writes trace information, a message, and event information to the listener specific output. |
| TraceEvent(TraceEventCache, String, TraceEventType, Int32, String, Object[]) | Writes trace information, a formatted array of objects and event information to the listener specific output. |
| TraceTransfer | Writes trace information, a message, a related activity identity and event information to the listener specific output. |
| Write(Object) | Writes the value of the object's ToString method to the listener you create when you implement the TraceListener class. |
| Write(String) | When overridden in a derived class, writes the specified message to the listener you create in the derived class. |
| Write(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. |
| Write(String, String) | Writes a category name and a message to the listener you create when you implement the TraceListener class. |
| WriteIndent | Writes the indent to the listener you create when you implement this class, and resets the NeedIndent property to false. |
| WriteLine(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. |
| WriteLine(String) | When overridden in a derived class, writes a message to the listener you create in the derived class, followed by a line terminator. |
| WriteLine(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. |
| WriteLine(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. |
For examples of how to implement a TraceListener, see the DefaultTraceListener, TextWriterTraceListener and the EventLogTraceListener classes.
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 you can 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 parameter, 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>
<add name="myListener" type="System.Diagnostics.TextWriterTraceListener" initializeData="TextWriterOutput.log" />
<remove name="Default" />
</listeners>
</trace>
</system.diagnostics>
</configuration>
For more information on using configuration files for tracing, see <system.diagnostics> Element.
 Note |
|---|
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. |
Inherit from this class to implement a custom listener for the Debug and Trace classes. At a minimum, you must implement the Write and WriteLine methods. Additionally, you can implement the Fail, Close and Flush methods.
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.
