XmlWriterTraceListener Class

Definition

public ref class XmlWriterTraceListener : System::Diagnostics::TextWriterTraceListener

public class XmlWriterTraceListener : System.Diagnostics.TextWriterTraceListener

type XmlWriterTraceListener = class
    inherit TextWriterTraceListener

Public Class XmlWriterTraceListener
Inherits TextWriterTraceListener

Inheritance

Object

MarshalByRefObject

TraceListener

TextWriterTraceListener

XmlWriterTraceListener

Examples

The following code example shows the use of the XmlWriterTraceListener class to write both escaped and non-escaped data to file logs.

using System;
using System.IO;
using System.Xml;
using System.Xml.XPath;
using System.Diagnostics;

class testClass
{
    static void Main()
    {
        File.Delete("NotEscaped.xml");
        TraceSource ts = new TraceSource("TestSource");
        ts.Listeners.Add(new XmlWriterTraceListener("NotEscaped.xml"));
        ts.Switch.Level = SourceLevels.All;
        string testString = "<Test><InnerElement Val=\"1\" /><InnerElement Val=\"Data\"/><AnotherElement>11</AnotherElement></Test>";
        XmlTextReader myXml = new XmlTextReader(new StringReader(testString));
        XPathDocument xDoc = new XPathDocument(myXml);
        XPathNavigator myNav = xDoc.CreateNavigator();
        ts.TraceData(TraceEventType.Error, 38, myNav);

        ts.Flush();
        ts.Close();

        File.Delete("Escaped.xml");
        TraceSource ts2 = new TraceSource("TestSource2");
        ts2.Listeners.Add(new XmlWriterTraceListener("Escaped.xml"));
        ts2.Switch.Level = SourceLevels.All;
        ts2.TraceData(TraceEventType.Error, 38, testString);

        ts2.Flush();
        ts2.Close();
    }
}

Imports System.IO
Imports System.Xml
Imports System.Xml.XPath
Imports System.Diagnostics



Class testClass
    
    Shared Sub Main() 
        File.Delete("NotEscaped.xml")
        Dim ts As New TraceSource("TestSource")
        ts.Listeners.Add(New XmlWriterTraceListener("NotEscaped.xml"))
        ts.Switch.Level = SourceLevels.All
        Dim testString As String = "<Test><InnerElement Val=""1"" /><InnerElement Val=""Data""/><AnotherElement>11</AnotherElement></Test>"
        Dim myXml As New XmlTextReader(New StringReader(testString))
        Dim xDoc As New XPathDocument(myXml)
        Dim myNav As XPathNavigator = xDoc.CreateNavigator()
        ts.TraceData(TraceEventType.Error, 38, myNav)

        ts.Flush()
        ts.Close()
        
        File.Delete("Escaped.xml")
        Dim ts2 As New TraceSource("TestSource2")
        ts2.Listeners.Add(New XmlWriterTraceListener("Escaped.xml"))
        ts2.Switch.Level = SourceLevels.All
        ts2.TraceData(TraceEventType.Error, 38, testString)
        
        ts2.Flush()
        ts2.Close()
    
    End Sub
End Class

Remarks

The XmlWriterTraceListener class converts tracing and debugging information into an XML-encoded text stream. The description of the XML output is shown in the tables that follow. You can use the Service Trace Viewer Tool (SvcTraceViewer.exe) to display the XML output.

You can create an XmlWriterTraceListener in your code. Alternatively, for .NET Framework apps, you can enable or disable an XmlWriterTraceListener through the application configuration file and then use the configured XmlWriterTraceListener in your application. To configure an XmlWriterTraceListener, edit the configuration file that corresponds to the name of your application. In this file, you can add or remove a listener, set the properties for a listener, or remove listeners. The configuration file should be formatted like the following example.

<configuration>  
  <system.diagnostics>  
    <trace autoflush="false" indentsize="4">  
      <listeners>  
        <add name="xmlListener"   
          type="System.Diagnostics.XmlWriterTraceListener"   
          initializeData="xmlOutput.xml"   
          traceOutputOptions="ProcessId, DateTime" />  
        <remove name="Default" />  
      </listeners>  
    </trace>  
  </system.diagnostics>  
</configuration>  

The XmlWriterTraceListener class inherits the Filter property from the base class TraceListener. The Filter property allows an additional level of trace output filtering at the listener. If there is a filter present, the Trace methods of the trace listener call the ShouldTrace method of the filter to determine whether to emit the trace.

The following table describes the elements and attributes of the XML output.

The following table shows the characters that are escaped in the XML output. Escaping occurs in all the elements and attributes with the exception of the DataItem element, which is not escaped if the object passed to the data parameter of the TraceData method is an XPathNavigator object. If an XPathNavigator is used for the data object, the MoveToRoot method is called and the entire root node is traced as unescaped data.

Constructors

Properties

Methods

Applies to