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Logger Class

When overridden in a derived form, provides functionality for loggers that handle events raised by the MSBuild engine.

System.Object
  Microsoft.Build.Utilities.Logger

Namespace:  Microsoft.Build.Utilities
Assembly:  Microsoft.Build.Utilities.v4.0 (in Microsoft.Build.Utilities.v4.0.dll)

[<AbstractClass>]
type Logger =  
    class 
        interface ILogger 
    end

The Logger type exposes the following members.

  NameDescription
Protected methodLoggerInitializes a new instance of the Logger class.
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  NameDescription
Public propertyParametersGets or sets the user-defined parameters of the logger.
Public propertyVerbosityGets or sets the level of detail to show in the event log.
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  NameDescription
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodFormatErrorEventGenerates an error message that is in the default format, from a BuildErrorEventArgs object.
Public methodFormatWarningEventGenerates a warning message that is in the default format, from a BuildWarningEventArgs object.
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodInitializeWhen overridden in a derived class, subscribes the logger to specific events.
Public methodIsVerbosityAtLeastDetermines whether the current Verbosity setting is at least the value that is passed in.
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodShutdownWhen overridden in a derived class, releases the resources allocated to the logger at the time of initialization or during the build.
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
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This abstract class provides default implementations for the methods and properties of the ILogger interface.

This class can only be instantiated in a derived form.

The following example shows how to write a basic logger that responds to build events.

using System;
using System.IO;
using System.Security;
using Microsoft.Build.Framework;
using Microsoft.Build.Utilities;

namespace MyLoggers
{
	// This logger will derive from the Microsoft.Build.Utilities.Logger class, 
	// which provides it with getters and setters for Verbosity and Parameters, 
	// and a default empty Shutdown() implementation. 
	public class BasicFileLogger : Logger
	{
		/// <summary> 
		/// Initialize is guaranteed to be called by MSBuild at the start of the build 
		/// before any events are raised. 
		/// </summary> 
		public override void Initialize(IEventSource eventSource)
		{
			// The name of the log file should be passed as the first item in the 
			// "parameters" specification in the /logger switch.  It is required
			// to pass a log file to this logger. Other loggers may have zero or more than  
			// one parameters. 
			if (null == Parameters)
			{
				throw new LoggerException("Log file was not set.");
			}
			string[] parameters = Parameters.Split(';');
			
			string logFile = parameters[0];
			if (String.IsNullOrEmpty(logFile))
			{
				throw new LoggerException("Log file was not set.");
			}
			
			if (parameters.Length > 1)
			{
				throw new LoggerException("Too many parameters passed.");
			}
			
			try
			{
				// Open the file 
				this.streamWriter = new StreamWriter(logFile);
			}
			catch (Exception ex)
			{
				if
				(
					ex is UnauthorizedAccessException
					|| ex is ArgumentNullException
					|| ex is PathTooLongException
					|| ex is DirectoryNotFoundException
					|| ex is NotSupportedException
					|| ex is ArgumentException
					|| ex is SecurityException
					|| ex is IOException
				)
				{
					throw new LoggerException("Failed to create log file: " + ex.Message);
				}
				else
				{
					// Unexpected failure 
					throw;
				}
			}

			// For brevity, we'll only register for certain event types. Loggers can also 
			// register to handle TargetStarted/Finished and other events.
			eventSource.ProjectStarted += new ProjectStartedEventHandler(eventSource_ProjectStarted);
			eventSource.TaskStarted += new TaskStartedEventHandler(eventSource_TaskStarted);
			eventSource.MessageRaised += new BuildMessageEventHandler(eventSource_MessageRaised);
			eventSource.WarningRaised += new BuildWarningEventHandler(eventSource_WarningRaised);
			eventSource.ErrorRaised += new BuildErrorEventHandler(eventSource_ErrorRaised);
			eventSource.ProjectFinished += new ProjectFinishedEventHandler(eventSource_ProjectFinished);
		}

		void eventSource_ErrorRaised(object sender, BuildErrorEventArgs e)
		{
			// BuildErrorEventArgs adds LineNumber, ColumnNumber, File, amongst other parameters 
			string line = String.Format(": ERROR {0}({1},{2}): ", e.File, e.LineNumber, e.ColumnNumber);
			WriteLineWithSenderAndMessage(line, e);
		}
		
		void eventSource_WarningRaised(object sender, BuildWarningEventArgs e)
		{
			// BuildWarningEventArgs adds LineNumber, ColumnNumber, File, amongst other parameters 
			string line = String.Format(": Warning {0}({1},{2}): ", e.File, e.LineNumber, e.ColumnNumber);
			WriteLineWithSenderAndMessage(line, e);
		}

		void eventSource_MessageRaised(object sender, BuildMessageEventArgs e)
		{
			// BuildMessageEventArgs adds Importance to BuildEventArgs 
			// Let's take account of the verbosity setting we've been passed in deciding whether to log the message 
			if ((e.Importance == MessageImportance.High && IsVerbosityAtLeast(LoggerVerbosity.Minimal))
				|| (e.Importance == MessageImportance.Normal && IsVerbosityAtLeast(LoggerVerbosity.Normal))
				|| (e.Importance == MessageImportance.Low && IsVerbosityAtLeast(LoggerVerbosity.Detailed))				
				)
			{
				WriteLineWithSenderAndMessage(String.Empty, e);
			}
		}

		void eventSource_TaskStarted(object sender, TaskStartedEventArgs e)
		{
			// TaskStartedEventArgs adds ProjectFile, TaskFile, TaskName 
			// To keep this log clean, this logger will ignore these events.
		}
		
		void eventSource_ProjectStarted(object sender, ProjectStartedEventArgs e)
		{
			// ProjectStartedEventArgs adds ProjectFile, TargetNames 
			// Just the regular message string is good enough here, so just display that.
			WriteLine(String.Empty, e);
			indent++;
		}

		void eventSource_ProjectFinished(object sender, ProjectFinishedEventArgs e)
		{
			// The regular message string is good enough here too.
			indent--;
			WriteLine(String.Empty, e);
		}
		
		/// <summary> 
		/// Write a line to the log, adding the SenderName and Message 
		/// (these parameters are on all MSBuild event argument objects) 
		/// </summary> 
		private void WriteLineWithSenderAndMessage(string line, BuildEventArgs e)
		{
			if (0 == String.Compare(e.SenderName, "MSBuild", true /*ignore case*/))
			{
				// Well, if the sender name is MSBuild, let's leave it out for prettiness
				WriteLine(line, e);
			}
			else
			{
				WriteLine(e.SenderName + ": " + line, e);
			}
		}
		
		/// <summary> 
		/// Just write a line to the log 
		/// </summary> 
		private void WriteLine(string line, BuildEventArgs e)
		{
			for (int i = indent; i > 0; i--)
			{
				streamWriter.Write("\t");
			}
			streamWriter.WriteLine(line + e.Message);
		}
		
		/// <summary> 
		/// Shutdown() is guaranteed to be called by MSBuild at the end of the build, after all  
		/// events have been raised. 
		/// </summary> 
		public override void Shutdown()
		{
			// Done logging, let go of the file
			streamWriter.Close();
		}

		private StreamWriter streamWriter;
		private int indent;
	}
}

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0

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.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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