Task Task Task Class

Definition

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

public ref class Task abstract : Microsoft::Build::Framework::ITask
public abstract class Task : Microsoft.Build.Framework.ITask
Public MustInherit Class Task
Implements ITask
Inheritance
TaskTaskTask
Derived
Implements

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;
		}
	}
}

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.

Constructors

Task() Task() Task()

Initializes a new instance of the Task class.

Task(ResourceManager) Task(ResourceManager) Task(ResourceManager)

Initializes a new instance of the Task class with the specified TaskResources.

Task(ResourceManager, String) Task(ResourceManager, String) Task(ResourceManager, String)

Initializes a new instance of the Task class with the specified TaskResources and HelpKeywordPrefix.

Properties

BuildEngine BuildEngine BuildEngine

Gets or sets the instance of the IBuildEngine object used by the task.

BuildEngine2 BuildEngine2 BuildEngine2

Gets the instance of the IBuildEngine2 object used by the task.

BuildEngine3 BuildEngine3 BuildEngine3

Gets the instance of the IBuildEngine3 object used by the task.

BuildEngine4 BuildEngine4 BuildEngine4

Gets the instance of the IBuildEngine4 object used by the task.

HelpKeywordPrefix HelpKeywordPrefix HelpKeywordPrefix

Gets or sets the prefix used to compose Help keywords from resource names.

HostObject HostObject HostObject

Gets or sets the host object associated with the task.

Log Log Log

Gets an instance of a TaskLoggingHelper class containing task logging methods.

TaskResources TaskResources TaskResources

Gets or sets the culture-specific resources associated with the task.

Methods

Equals(Object) Equals(Object) Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
Execute() Execute() Execute()

When overridden in a derived class, executes the task.

GetHashCode() GetHashCode() GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType()

Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString()

Returns a string that represents the current object.

(Inherited from Object)

Applies to