.NET Framework Class Library
Task Class

When overridden in a derived form, provides functionality for tasks.

Inheritance Hierarchy
SystemObject
  Microsoft.Build.UtilitiesTask
    More...

Namespace:   Microsoft.Build.Utilities
Assembly:  Microsoft.Build.Utilities.v4.0 (in Microsoft.Build.Utilities.v4.0.dll)
Syntax
Public MustInherit Class Task _
	Implements [%$TOPIC/ms126274_en-us_VS_110_2_0_0_0_0%]
public abstract class Task : [%$TOPIC/ms126274_en-us_VS_110_2_0_1_0_0%]
public ref class Task abstract : [%$TOPIC/ms126274_en-us_VS_110_2_0_2_0_0%]
[<[%$TOPIC/ms126274_en-us_VS_110_2_0_3_0_0%]>]
type Task =  
    class 
        interface [%$TOPIC/ms126274_en-us_VS_110_2_0_3_0_1%] 
    end

The Task type exposes the following members.

Constructors
  NameDescription
Protected method TaskInitializes a new instance of the Task class.
Protected method Task(ResourceManager)Initializes a new instance of the Task class with the specified TaskResources.
Protected method Task(ResourceManager, String)Initializes a new instance of the Task class with the specified TaskResources and HelpKeywordPrefix.
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Properties
  NameDescription
Public property BuildEngineGets or sets the instance of the IBuildEngine object used by the task.
Public property BuildEngine2Gets the instance of the IBuildEngine2 object used by the task.
Public property BuildEngine3Gets the instance of the IBuildEngine3 object used by the task.
Public property BuildEngine4Gets the instance of the IBuildEngine4 object used by the task.
Protected property HelpKeywordPrefixGets or sets the prefix used to compose Help keywords from resource names.
Public property HostObjectGets or sets the host object associated with the task.
Public property LogGets an instance of a TaskLoggingHelper class containing task logging methods.
Protected property TaskResourcesGets or sets the culture-specific resources associated with the task.
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Methods
  NameDescription
Public method Equals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Public method ExecuteWhen overridden in a derived class, executes the task.
Protected method FinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method GetHashCodeServes as the default hash function. (Inherited from Object.)
Public method GetTypeGets the Type of the current instance. (Inherited from Object.)
Protected method MemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public method ToStringReturns a string that represents the current object. (Inherited from Object.)
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Remarks

This abstract class provides default implementations for the methods and properties of the ITask interface.

This class can only be instantiated in a derived form.

Examples

The following example shows the code for a task that creates one or more directories.

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

namespace Microsoft.Build.Tasks
{
	/*
	 * Class: MakeDir
	 *
	 * An MSBuild task that creates one or more directories.
	 *
	 */ 
	public class MakeDir : Task
	{
	    // The Required attribute indicates the following to MSBuild: 
	    //	     - if the parameter is a scalar type, and it is not supplied, fail the build immediately 
	    //	     - if the parameter is an array type, and it is not supplied, pass in an empty array 
	    // In this case the parameter is an array type, so if a project fails to pass in a value for the  
            // Directories parameter, the task will get invoked, but this implementation will do nothing, 
            // because the array will be empty.
		[Required]
            // Directories to create. 
		public ITaskItem[] Directories
		{
			get
			{
				return directories;
			}

			set
			{
				directories = value;
			}
		}

		// The Output attribute indicates to MSBuild that the value of this property can be gathered after the 
		// task has returned from Execute(), if the project has an <Output> tag under this task's element for  
		// this property.
		[Output]
		// A project may need the subset of the inputs that were actually created, so make that available here. 
		public ITaskItem[] DirectoriesCreated
		{
			get
			{
				return directoriesCreated;
			}
		}

		private ITaskItem[] directories;
		private ITaskItem[] directoriesCreated;

		/// <summary> 
		/// Execute is part of the Microsoft.Build.Framework.ITask interface. 
		/// When it's called, any input parameters have already been set on the task's properties. 
		/// It returns true or false to indicate success or failure. 
		/// </summary> 
		public override bool Execute()
		{
			ArrayList items = new ArrayList();
			foreach (ITaskItem directory in Directories)
			{
				// ItemSpec holds the filename or path of an Item 
				if (directory.ItemSpec.Length > 0)
				{
					try
					{
						// Only log a message if we actually need to create the folder 
						if (!Directory.Exists(directory.ItemSpec))
						{
							Log.LogMessage(MessageImportance.Normal, "Creating directory " + directory.ItemSpec);
							Directory.CreateDirectory(directory.ItemSpec);
						}

						// Add to the list of created directories
						items.Add(directory);
					}
					// If a directory fails to get created, log an error, but proceed with the remaining  
					// directories. 
					catch (Exception ex)
					{
						if (ex is IOException
							|| ex is UnauthorizedAccessException
							|| ex is PathTooLongException
							|| ex is DirectoryNotFoundException
							|| ex is SecurityException)
						{
							Log.LogError("Error trying to create directory " + directory.ItemSpec + ". " + ex.Message);
						}
						else
						{
							throw;
						}
					}
				}
			}

			// Populate the "DirectoriesCreated" output items.
			directoriesCreated = (ITaskItem[])items.ToArray(typeof(ITaskItem));

			// Log.HasLoggedErrors is true if the task logged any errors -- even if they were logged  
			// from a task's constructor or property setter. As long as this task is written to always log an error 
			// when it fails, we can reliably return HasLoggedErrors. 
			return !Log.HasLoggedErrors;
		}
	}
}
Version Information

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0
Platforms

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.

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