ITaskItem 接口

定义

此接口定义可以由任务使用和发出的项目项。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
派生
属性

示例

下面的示例演示用于创建一个或多个目录的任务的代码。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;
        }
    }
}

注解

ITaskItem 生成过程中创建的对象数可能与项目文件中声明的项不完全相对应,原因如下:The number of ITaskItem objects created during a build may not correspond exactly to items declared in a project file for the following reasons:

  • 任务有时会创建未在项目文件中声明的项。Tasks sometimes create items that were not declared in the project file.

  • 在项目文件中,可以使用通配符声明项集合,这可能会在生成时创建许多项。An item collection can be declared in the project file with wildcards, which could create many items when built.

属性

ItemSpec

获取或设置项“规格”,例如对于基于磁盘的项,这将是文件路径。Gets or sets the item "specification" e.g. for disk-based items this would be the file path.

MetadataCount

获取该项的元数据的条数。Gets the number of pieces of metadata on the item. 包含自定义元数据和内置元数据。Includes both custom and built-in metadata.

MetadataNames

获取该项上所有元数据的名称。Gets the names of all the metadata on the item. 包含内置元数据,如“FullPath”。Includes the built-in metadata like "FullPath".

方法

CloneCustomMetadata()

获取自定义元数据的集合。Get the collection of custom metadata. 这不包含内置元数据。This does not include built-in metadata.

CopyMetadataTo(ITaskItem)

允许将一个项的自定义元数据复制到另一个项。Allows custom metadata on the item to be copied to another item.

GetMetadata(String)

允许查询此项的元数据的值。Allows the values of metadata on the item to be queried.

RemoveMetadata(String)

允许删除对项设置的自定义元数据。Allows the removal of custom metadata set on the item.

SetMetadata(String, String)

允许在此项上设置一段自定义元数据。Allows a piece of custom metadata to be set on the item.

适用于