ITaskItem Interface

Definition

Namespace:

Microsoft.Build.Framework

Assembly:

Microsoft.Build.Framework.dll

Package:

Microsoft.Build.Framework v17.11.4

Source:

ITaskItem.cs

This interface defines a project item that can be consumed and emitted by tasks.

public interface class ITaskItem

[System.Runtime.InteropServices.ComVisible(true)]
[System.Runtime.InteropServices.Guid("8661674F-2148-4F71-A92A-49875511C528")]
public interface ITaskItem

[<System.Runtime.InteropServices.ComVisible(true)>]
[<System.Runtime.InteropServices.Guid("8661674F-2148-4F71-A92A-49875511C528")>]
type ITaskItem = interface

Public Interface ITaskItem

Derived

Microsoft.Build.Execution.ProjectItemInstance

Microsoft.Build.Framework.ITaskItem2

Microsoft.Build.Utilities.TaskItem

Attributes

ComVisibleAttribute GuidAttribute

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

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.

Properties

ItemSpec	Gets or sets the item "specification" e.g. for disk-based items this would be the file path.
MetadataCount	Gets the number of pieces of metadata on the item. Includes both custom and built-in metadata.
MetadataNames	Gets the names of all the metadata on the item. Includes the built-in metadata like "FullPath".

Methods

CloneCustomMetadata()	Get the collection of custom metadata. This does not include built-in metadata.
CopyMetadataTo(ITaskItem)	Allows custom metadata on the item to be copied to another item.
GetMetadata(String)	Allows the values of metadata on the item to be queried.
RemoveMetadata(String)	Allows the removal of custom metadata set on the item.
SetMetadata(String, String)	Allows a piece of custom metadata to be set on the item.