ITaskItem Interface

Defines an MSBuild item that can be consumed and emitted by tasks.

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

[<ComVisibleAttribute(true)>]
[<GuidAttribute("8661674F-2148-4F71-A92A-49875511C528")>]
type ITaskItem =  interface end

The ITaskItem type exposes the following members.

  NameDescription
Public propertyItemSpecGets or sets the item specification.
Public propertyMetadataCountGets the number of metadata entries associated with the item.
Public propertyMetadataNamesGets the names of the metadata entries associated with the item.
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  NameDescription
Public methodCloneCustomMetadataGets the collection of custom metadata.
Public methodCopyMetadataToCopies the custom metadata entries to another item.
Public methodGetMetadataGets the value of the specified metadata entry.
Public methodRemoveMetadataRemoves the specified metadata entry from the item.
Public methodSetMetadataAdds or changes a custom metadata entry to the item.
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The number of ITaskItem objects created during a build may not correspond exactly to items declared in a project file for the following reasons:

  • Tasks sometimes create items that were not declared in the project file.

  • An item collection can be declared in the project file with wildcards, which could create many items when built.

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;
		}
	}
}

.NET Framework

Supported in: 4.5.2, 4.5.1, 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.

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