IEventSource Interface
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IEventSource Interface

 

Defines the events raised by the build engine. Loggers receive an object implementing this interface in their Initialize method and use it to subscribe to the events they are interested in receiving.

Namespace:   Microsoft.Build.Framework
Assembly:  Microsoft.Build.Framework (in Microsoft.Build.Framework.dll)

public interface IEventSource

NameDescription
System_CAPS_pubeventAnyEventRaised

Occurs when a build raises any other type of build event.

System_CAPS_pubeventBuildFinished

Occurs when a build finishes.

System_CAPS_pubeventBuildStarted

Occurs when a build starts.

System_CAPS_pubeventCustomEventRaised

Occurs when a build raises a custom event.

System_CAPS_pubeventErrorRaised

Occurs when a build raises an error.

System_CAPS_pubeventMessageRaised

Occurs when a build raises a message.

System_CAPS_pubeventProjectFinished

Occurs when a project finishes building.

System_CAPS_pubeventProjectStarted

Occurs when a project starts building.

System_CAPS_pubeventStatusEventRaised

Occurs when a build raises a status event.

System_CAPS_pubeventTargetFinished

Occurs when a target finishes building.

System_CAPS_pubeventTargetStarted

Occurs when a target starts building.

System_CAPS_pubeventTaskFinished

Occurs when a task completes execution.

System_CAPS_pubeventTaskStarted

Occurs when a task begins execution.

System_CAPS_pubeventWarningRaised

Occurs when a build raises a warning.

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
Available since 2.0
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