ITaskItem Schnittstelle

Definition

Definiert ein MSBuild-Element, das von Aufgaben aufgenommen und ausgegeben werden kann.Defines an MSBuild 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
type ITaskItem = interface
Public Interface ITaskItem
Abgeleitet
Attribute

Beispiele

Das folgende Beispiel zeigt den Code für einen Task, der ein oder mehrere Verzeichnisse erstellt.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;
        }
    }
}

Hinweise

Die Anzahl von ITaskItem Objekten, die während eines Builds erstellt werden, entspricht möglicherweise nicht exakt den in einer Projektdatei deklarierten Elementen aus den folgenden Gründen: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 erstellen manchmal Elemente, die nicht in der Projektdatei deklariert wurden.Tasks sometimes create items that were not declared in the project file.

  • Eine Element Auflistung kann in der Projektdatei mit Platzhaltern deklariert werden, wodurch viele Elemente erstellt werden können, wenn Sie erstellt werden.An item collection can be declared in the project file with wildcards, which could create many items when built.

Eigenschaften

ItemSpec

Ruft die Elementspezifikation ab oder legt sie fest.Gets or sets the item specification.

MetadataCount

Ruft die Anzahl der Metadateneinträge ab, die dem Element zugeordnet sind.Gets the number of metadata entries associated with the item.

MetadataNames

Ruft die Namen der Metadateneinträge ab, die dem Element zugeordnet sind.Gets the names of the metadata entries associated with the item.

Methoden

CloneCustomMetadata()

Ruft die Auflistung benutzerdefinierter Metadaten ab.Gets the collection of custom metadata.

CopyMetadataTo(ITaskItem)

Kopiert die benutzerdefinierten Metadateneinträge in ein anderes Element.Copies the custom metadata entries to another item.

GetMetadata(String)

Ruft den Wert des angegebenen Metadateneintrags ab.Gets the value of the specified metadata entry.

RemoveMetadata(String)

Entfernt den angegebenen Metadateneintrag aus dem Element.Removes the specified metadata entry from the item.

SetMetadata(String, String)

Fügt dem Element einen benutzerdefinierten Metadateneintrag hinzu oder ändert diesen.Adds or changes a custom metadata entry to the item.

Gilt für: